Depends on the coder.
Most sources I've seen sold are a few hundred dollars each with additional features/fixes ranging between 20-300 usd per feature/fix.
Honestly you're best off learning to do things yourself but if you've got cash to burn then I suppose it would save you some time.
My only advice there would be don't spend your cash on fixing up a **** source... spend your cash on adding (well coded) features to a GOOD source.
Disclaimer: Public sources are not good
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I'll throw around a few of the prices I've been offered or have heard for different things...
Note: just going off some prices I've heard people payed. I can't confirm these unless I specify so
Fully working 1.0 source (full or almost full featured using binary database) ~900 usd
Custom Current patch source with medium features ~400-500 usd
Full soul/refinery system: 300 usd (I've been offered it. I refused because I don't like working with old trinity sources and didn't have time)
Full Poker: 200-400 usd (what I've been offered as well as what I've heard people saying they'd pay for it
Hell even small fixes/scripts from trustworthy people who know what they are doing will usually be 20-50+. Personally I try to avoid doing anything for less than that because if not it's simply not worth my time.
