Originally Posted by
Andy_K
Check your local Craigslist for a late 80's/early 90's mountain bike made by Specialized, Trek or Giant. These things are great for commuting, and you can often find them in good shape for around $100. You might want to replace the tires, tubes, cables and brake pads to have it running like a new bike, but even if you have the LBS do the work it'll be cheaper than a low-end new bike. A lot of these can even be converted to single speed (depending on the dropouts). Avoid anything with suspension.
^^^This! Looks like you're taking the advice to heart:
Originally Posted by
coopthepirate
My advice - call the seller and arrange a test ride right away. That is a decent, well-equipped bike. If the bike fits and nothing feels like it's going to fall off, buy it. Take it to your LBS and pay 50 bucks for a tune up (plus parts, of course). You should have enough money left over out of your $300 budget for a lock (a u-lock/cable combo is a good bet), some lights, and a helmet. If you can afford it slap on some fenders and a rack.
Forget single speed for now; you might just find that you like the gears. You can always switch it to SS when time/money permits, or you can save your pennies for one of those $700 single speeds that the salesman showed you and keep the MTB for backup.