Good news! I won Gradius Gaiden on eBay, mint, for $25!

Bad news! I can't play it on my friggin' American PS1!

I could modify my PS1, but it's one of the newer models... not sure if a mod chip would work on one of those, so I think the better option here would be to gain a Japanese PS1. I THINK it's the better option... I'm a total newbie to importing, so I have a few questions:

1. What is the general price range of a Japanese PS1?

2. Do I need a special adaptor to make the plugs for the Japanese machine fit?

3. I already have an American PSONE and PS2... I'm a little sketchy on owning three Playstations. Should I sell my American PSONE?

I don't know what other questions I could ask... if anyone else has any suggestions for me on this matter, it would be appreciated. Thanks.