Tax Lien on propertie - holder want entire pay off

[Uwe S.]

Found an mixed use building with 8 units and a tax lien of $28k on it.
Mostly units rented (2 vacant) and bring in some money. I could buy this house but cant pay off the tax lien, so I asked the lien holder for installment plan but he rejected he want all cash.
So my question is, where can i find someone who buy this tax lien and enables a installment with 18% interest?

-Uwe