I don't know the kind of weight you're working with, but I find that a
Swiss Ball can work well as a weight bench- even better because you're training your sense of balance at the same time. It's also good for stretching and ab work, and it's CHEAP- I got my heavy duty swiss ball at Wal-mart for... $15 maybe?
If you feel like you must have a weight bench, I don't see them being really hard to make with some plywood and batting (padding) and pleather. However, not having done this myself, I can't say for sure.
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Sage knows our mythic history, King Arthur's and Sir Caradoc's
She answers hard acrostics, has a pretty taste for paradox
She quotes in elegiacs all the crimes of Heliogabalus
In conics she can floor peculiarities parabolous
-C'hi