If you want larger wheels and you don't want to spend much, look for a set of "Hydra" wheels from a 740 Turbo or 940 Turbo. They're 16"x6.5", and they will fit your car without any modifications. Click here
to see them on a 240.
Team Dynamics also makes wheels in the correct offset and bolt pattern for the 240 (which is 20mm and 5x108mm, respectively). Check with www.victoriatire.com
but if you do order from them, make sure they have them in stock, or at least in the country. I've heard complaints that when they have to order the wheels, it takes forever.
I think www.tirerack.com
still sells a few wheels for the 240. The Borbet Type E was a popular choice. It's a basic 5 spoke silver wheel that came in 15x7 and maybe 16x7 sizes for the 240.
*edit* TireRack has the Type E
15x7 @ $109ea, ASA JS1
15x7 @ $115, 16x7 @ $135, and AT Italia 5 Razze
15x7 @ $119, 16x7.5 @ $139.
Those are the only inexpensive sources I'm aware of. If you can score a cheap set of OEM or aftermarket wheels/tires from a FWD Volvo, it will be another $250-$300 for adapters.
Personally, I'm happy with the 240 Turbo wheels with a fresh coat of paint.