Paying for mods is against the rules, but you can certainly request one here in the Help & Requests section. Tip jars are fine though, and if a modder does have one, you can drop them a couple of bucks if you feel so inclined. But directly paying/charging for mods is against the rules.
Yeah I tried putting my face in the game with replacing someone else's player model that closely resembled mine and it doesn't look that good but it also doesn't look that bad. I'd still like to be able to scan myself in the PC version then edit the texture if needed. Hopefully NBA 2K16 will also give us that feature for PC even if I have to buy a separate camera for it.