I want to get a bicycle, to take rides with the g/f and to up my cardio and workout because i'm going to Marine OCS this summer in PLC. Plan to ride it to school as well and maybe to work if i can land a job close by.

I'm in Orlando and dont know of any Bike shops, so i went to walmart and saw a couple of bikes that looked ok. Im only able to spend $150 too, so that is a factor.



www.walmart.com/catalog/product.do?product_id=3663046

Which is just at $150


and



www.walmart.com/catalog/product.do?product_id=4029278

and




www.walmart.com/catalog/product.do?product_id=4016707


Which type of bike would be the best workout? Or better for long distances, say up to 10-20 miles? Will a mountain bike still be ok to ride on the sidewalk/street and not fatigue me quickly compared to the street bike i am looking at? Or is that not really a factor?

And lastly, what do you guys think of the bikes im looking at? Opinions on which i should get/stay away from?

Thanks.

I am a pretty big guy (6'6" 250), so I really enjoy the front and rear suspension on the mountain bike I have. I ride it 12.5mi. to work one way in the city. no problems at all. Of those you showed, I would pick the one with the most rugged frame, and run one of the gel seats or covers as it will really help.

ETA: the tougher wheel of the mountian bikes might be better for going up and down curbs too.