55mm prime

After seeing a few great portraits from a couple different friends, who use this 1.8 prime lens..I want one! Any recs as to what to buy (or where to buy it( to fit my Rebel XSi ? Thanks

You mean 50mm? http://www.amazon.com …Camera-Lens/dp/B00007E7JU has it for under $100.

55mm is discontinued a long time ago.

There is a lot of information implicit in your post that suggests to me that we could be of more service to you if you posted some portraits you have taken with your existing lens(es) first, described what you find unsatisfactory about them, and allowed us to point out the best direction for you to take with whatever budget you may have.

Yes..the 50 mm..sorry!
I haven't gotten into taking portraits much yet..but I do like that look where the subject is tack sharp, with the background being blurred, and my lens (50-200mm) isn't allowing for that!

You can easily get blurred background portraits with your 50-200mm. Just stand back a bit, shoot the subject at 200mm so they fill a bit of the frame, and make sure the background is far back from the subject (and shoot with your widest aperture)