What is the tax rate on tax lien redemption proceeds?

Basically I am getting into tax lien certs a lot…but I am really concerned about how much will be taken for taxes at redemption. Basically, I am thinking wow…18% sounds awesome. Drop a 1000 dollars and get 1180 in return if they redeem. But what part of those proceeds are taken by taxes? Also is there a way to re-invest the proceeds without incuring tax issues?

Thanks guys

Do not enough people do Tax Lien cert’s here?