Hi Nelie --
Here's my experience... Don't buy a cheap bike at WallyWorld or Target, I agree with the girls 100% there...
I have a mountain bike and I like it, BUT if you're going to get a mountain bike and not use it in rough terrain like in the mountains, don't go with the mountain type bikes, the balloon tires with all the nubs are for the traction which you would need in a rough terrain. If you're going to use your bike in town on the roads or smooth bike paths, my suggestion is to get a hybrid type bike that has medium size tires, not the skinny tires like the racer bikes but a tire inbetween the mountain bike and the racer... I know this because I never ever go in rough terrain with my mountain bike, although I love it, makes me feel like I'm dragging and is difficult to pedal even if it is a very good bike...The only cross country stuff I've ever done is go through tall grass,
, and if I have it in a low gear it's very smooth..
Go to a reputable bike store and they'll know what a "hybrid" is...
I also feel very ready to upgrade to a "street" type bike or race like we use to call them... There is only one bicycle shop in town here and the cheapest street bike was $1100
... and it was on sale... I'll wait till we go out of town to check them out at other stores... On the other hand a very good hybrid runs about $300, and that's Canadian $, so I can imagine in the States you can get an even better deal...
Ok I've rambled, time for bed...