Looking to spend $200 - $300 on a mountain style bike that will likely never see the mountains.

Will be on sidewalks and occasional neighborhood trails.

Any suggestions?

For that price range and riding style, pretty much any brand of mountain or hybrid will work. There's always the Wal Mart, Target no name brands if you want new, or you can spend some time on the used bike market and find a great deal on a used Specialized, Trek, Giant, etc. sometimes people let great bikes go for next to nothing (just to free up space).

You can probably find a decent deal on a K2 at Sports Authority. It will have OK entry components that you aren't likely to wear out soon from that riding. However, keep an eye on your tires and change your tubes after 100 miles on the new ones. You can buy good tubes later that will last longer.

Keep in mind that those components work but don't stay in tune very well. You can also find a good used bike on craigslist by someone who bought but didn't follow through on an entry level bike. If you go that route, change the tires, tubes, and have the bike serviced.

I second Sweep's idea. There are lots of decent bikes on Craigslist in that price range or below.

http://collegestation.craigslist.org/bik/4410378870.html

http://collegestation.craigslist.org/bik/4409102036.html

http://collegestation.craigslist.org/bik/4417234483.html

Don't buy from Walmart/Target/etc.