If you'd like to determine exactly how much Influence it will cost you to outfit your hero, I created an Excel Spreadsheet that lets you enter the Level of enhancement, TO/DO/SO, and then how many of each type of enhancement (Acc, Dam, Etc.) and it will tell you how many total Enhancements and the total cost of Influence.
Download a Zip'd copy of it HERE or click the "Hero Helper" link in my Sig for this as well as some additional files to help your journey through Paragon City. 
Unexplained Investigations Supergroup on VICTORY!
UI Cards
Snuph's Hero Helpers
Just wanted to say thanks for this guide. It really helped A LOT!
Level 50s:
BlackSpectre, Dark Defender (Guardian)
Thorin, Invul/Axe Tank (Justice)
Volcano Juice, Fire/Stone Tank
Professor ?, Mind/FF Controller
Stone Forge, Stone/Fire Tank
This guide is great, and at first glance it looks REALY Ominouse... however once you get past 32 you really start earning ALOT of influence per lvl jump... just get out of SG mode for 3 or 4 missions and you will be back on top.
ALSO, if you use your respec's wisely... you can respec your charecter at key lvls to sell back all your old enhancements and have plenty of influence all lvls while staying in SG mode. I remember one time I made a charecter and got really lucky: Got a free respec for a new patch, used it at 22 to sell all my DO's back and buy 25 SO's... got the 24 respec and used it at 32 to sell all my 30's back and buy 35's... then got the other 34 respec... used it at 37 to sell back my 35's... then get the 44 respec and use it at 47 to sell my 45s... to get 50s...
By the last respec I ended up getting something like 3.5 million for selling back my lvl 45 enhancements...
I have always wondered how much influence it takes to fully slot a character. Especially when SG mode deprives you of so much in the later game. How much Influence is required to buy shiny new enhancements is a good question. This post attempts to answer it.
The following numbers are based on a character throwing away all their old enhancements as soon as they can get new ones, and buying DO's & SO's as soon as possible. There are ways and means to reduce the cost of a new set of enhancements, either with a respec, or by not rushing to upgrade everything all at once. These things aren't discussed here as this is merely an at-a-glance view to how much it could potentially cost to upgrade everything.
Enhancements have varying costs based on what they enhance. Damage & Healing for example, are the most expensive, with accuracy a close second. Jump Distance, Run Speed, Hold Duration etc all cost less than damage, so the prices quoted below are worst case, and also assume you are slotting everything. (Some folks don't slot Rest or Brawl at all at later levels.) I have listed the cost for an Accuracy Enhancement, a Damage Enhancement (most expensive) and a KNockback Enhancement (cheapest).
Negami's CoV Enhancement Price Guide details the difference in cost between each one, so it is possible to calculate exactly how much it would cost...
Next to each level breakpoint, I put in brackets where I got my prices from. There may be other places to get them cheaper, but as this is just a rough guide, I figure it's not worth worrying about.
Finally, I would highly recommend ZealotOnAStick's Universal Enhancement Guide as a good place to get a lot more detail. (Zealot - If you ever re-write that guide and would like to include these numbers, feel free!)
Level 2 (Atlas Trainer)
At level 2, you can buy level 5 Training Enhancements. You will need 8 of them to fully slot your character. Kheldians will need 9.
Acc TO costs 576 Inf
Dam TO costs 500 Inf
Knockback TO costs 156 Inf
8 Slots @ 500 Inf = 4,000 to fully slot out.
Level 7 (Atlas Trainer)
At level 7, you can buy level 10 Training Enhancements. You will need 15 of them to fully slot your character. Kheldians will need 19 if they have a Nova form.
Acc TO costs 1,056 Inf
Dam TO costs 1,000 Inf
Knockback TO costs 330 Inf
15 Slots @ 1,000 Inf = 15,000 to fully slot out.
Level 12 (Skyway Tech shop)
At level 12, you can buy level 15 Dual Origin Enhancements. You will need 22 of them to fully slot your character. Kheldians will need 27 if they have a Nova form.
Acc DO costs 6,129 Inf
Dam DO costs 5,985 Inf
Knockback DO costs 1,976 Inf
22 Slots @ 5,985 Inf = 131,670 to fully slot out.
Level 17 (Skyway Tech shop)
At level 17, you can buy level 20 Dual Origin Enhancements. You will need 30 of them to fully slot your character. Kheldians will need 35 if they have a Nova form.
Acc DO costs 8,044 Inf
Dam DO costs 7,980 Inf
Knockback DO costs 2,634 Inf
30 Slots @ 7,980 Inf = 239,400 to fully slot out.
Level 22 (Talos Mutant Shop)
At level 22, you can buy level 25 Single Origin Enhancements. You will need 37 of them to fully slot your character. Kheldians will need 48 if they have a Nova form and a Dwarf form.
Acc SO costs 29,952 Inf
Dam SO costs 30,000 Inf
Knockback SO costs 9,900 Inf
37 Slots @ 30,000 Inf = 1,110,000 to fully slot out.
Level 27 (Talos Mutant Shop)
At level 27, you can buy level 30 Single Origin Enhancements. You will need 45 of them to fully slot your character. Kheldians will need 56 if they have a Nova form and a Dwarf form.
Acc SO costs 35,712 Inf
Dam SO costs 36,000 Inf
Knockback SO costs 11,880 Inf
45 Slots @ 36,000 Inf = 1,620,000 to fully slot out.
Level 32 (Founders Falls Contact)
At level 32, you can buy level 35 Single Origin Enhancements. You will need 53 of them to fully slot your character. Kheldians will need 64 if they have a Nova form and a Dwarf form.
Acc SO costs 41,472 Inf
Dam SO costs 42,000 Inf
Knockback SO costs 13,860 Inf
53 Slots @ 42,000 Inf = 2,226,000 to fully slot out.
Level 37 (Founders Falls Contact)
At level 37, you can buy level 40 Single Origin Enhancements. You will need 66 of them to fully slot your character. Kheldians will need 77 if they have a Nova form and a Dwarf form.
Acc SO costs 47,232 Inf
Dam SO costs 48,000 Inf
Knockback SO costs 15,840 Inf
66 Slots @ 48,000 Inf = 3,168,000 to fully slot out.
Level 42 (Ghost Falcon - PI)
At level 42, you can buy level 45 Single Origin Enhancements. You will need 77 of them to fully slot your character. Kheldians will need 88 if they have a Nova form and a Dwarf form.
Acc SO costs 52,992 Inf
Dam SO costs 54,000 Inf
Knockback SO costs 17,820 Inf
77 Slots @ 54,000 Inf = 4,158,000 to fully slot out.
Level 47 (Ghost Falcon - PI)
At level 47, you can buy level 50 Single Origin Enhancements. You will need 88 of them to fully slot your character. Kheldians will need 99 if they have a Nova form and a Dwarf form.
Acc SO costs 58,752 Inf
Dam SO costs 60,000 Inf
Knockback SO costs 19,800 Inf
88 Slots @ 60,000 Inf = 5,280,000 to fully slot out.
As I've said above, this is probably a worst case number as not many folks just have slotted ACC & DAM. It is merely a rough number to keep in your head as a guide to what you should be saving for. At least then you may have change to go to the tailor for that nose job you were after...
-H