What adapters do I get?

I know Ill need a set of adapters to put aftermarket rims on my Bravada, how do I know which ones to get? Id prefer to buy them online, as it is so much cheaper....
Car is a 1997 Oldsmobile Bravada, rims are 20"

you said on the other thread that you're getting wire wheels. Wire wheel manufacturers make lug faces that attach to the wheels with almost every bolt pattern that there is. Contact the wheel manufacturer to get the right lug face.

Thing is, Im sure they will be very expensive direct from Dayton. I was hoping someone might know of a site that tells what size adapter I need, so that I can shop around for the best price. Thanks for the term "lug face" though, Ill do some searching with that.

also, the bolt pattern you're looking for is 5 x 4.75" (120.7mm)