They're too expensive? No, that's just not true. Be glad you picked one of the easiest (financially) instruments to own.
Just go get an 4 string American Fender Precision bass.
If you plan on getting serious about playing bass, eventually you will need this in your arsenal. There is no substitute.
You could go get a sparkly Ibanez one for cheap. But after you've gutted the pickups and still can't get a decent tone, you'll understand.
You could go get one that is black and jagged and looks evil, but then you'd realize a couple of months later it still sounds like shit.
You could go get a Musicman and play that funky music, but you'd still need the P-Bass to play rock or jazz.
About $400 used, and it'll always be worth that. Ask your Dad about his IRA portfolio losses in the last couple of years, and then let him know about the rock-solid Fender P Bass.