IMHO, get stock wheels. You can buy them cheaply and you know they will fit. Any mk5+ Golf, JSW, Jetta wheels will fit fine. Mk4 and B5 Passat will not.
Stock wheels are a little heavy but they're worth the low price. If you want to spend a little more, get light weight wheels, they work better on all levels but are more expensive.
The most active wheel classifieds are on craigslist or vwvortex's wheel classifieds.