Don't let the high prices of games hold you back.
The real reason the Dreamcast failed was its absolute lack of copy protection, relying only on the slightly higher capacity of their discs to limit copying. Sega failed to see the obvious signs on the horizon of sharing digital files over the 'internet' (as they called it in those days), so games trickled out online. All you needed was some bandwidth and a stack of CD-Rs. File sharing since then has only become better...
That said, the DC really is a fun machine, especially if you are into Japanese games (I'm not). The original version of Rez, Sonic Adventure, and of course Sega Sports games can make it fun to hook up every now and then.
I've found 2 of them used (one for $60, one for $6), and have picked up little extras along the way at flea markets and thrift stores (VMUs, s-video cables).
$99 isn't a steal or anything... unless you think a sealed Dreamcast is going to be worth big money someday...