Oh just go and buy a simple adjustable bench!!! Basic benches are not that expensive, or use one of those cheap lawn chairs with the adjustable back. <G>
There are some benches on ebay, try:
http://search.ebay.com/search/search.dll?
MfcISAPICommand=GetResult&So...
That will give you tons of choices.

Some cheap, some expensive and any of the regular dealers will usually do private sales so you don't have to bid.
Personally, I bought an adjustable weight bence with bar rack and leg attachements for only $100.00 from Oshmans sporting goods in Austin! It adjusts up for doing inclines.