I have a Specialized Globe (3 speeds) I bought on craigslist for $150 used. I then got a tune up for $90. I wanted to use it for commuting and did for a while but it felt too slow and the seat is too low. I know very little about bikes and think I spent too much on this. Should I just sell the bike and get one with a bigger frame or buy a taller seat post b/c the current one is way too short? How much do you think this bike is worth? I saw similar bikes on craigslist but not the exact one. I can post a pic of it.

Also, if I buy another bike what are specific things to look for? I’m looking for a sturdy cheap bike that is FAST and would like to get it ASAP. The area I live in has some hills so would it be better to get a bike with more speeds?

Your help is GREATLY appreciated.

Thank you!