KH 20 and a 36" UK, how much do people sell them on here for?

I’m looking to buy both these unicycles over the next few months, but not immediatly and am wondering how much money I will need to save up for them. I wan’t them in good condition, but used. I don’t mind what model KH or 36 as long as they are not too expensive. For the KH20 i preferably want one of the earlier models (2007 or so).

I want to pay under £200 for the 36 and under £250 for the KH.

Thanks a lot.