It really depends on how much you want to spend. I have a Nikon 16x47x60. It is VERY clear. I got it a few years ago for around $400 (for the kit) It came with a tripod and carrying case. You can get a window mount for it for around $30.
I really can't give any input on alot of the real inexpensive scopes...but a buddy mine has a Bushnell (not sure which model) but it was about $120 and there is no comparison between the two. I guess it's up to you. Check out http://natchezss.com/ they usually have real good optics prices, especially when they put them on sale.