I have a cheap one (less than but most of $100). It is fun to use, but it is a lot of work to clean it after you use it. Some of it disassembles for cleaning, but the main body doesn’t and it does get covered in meat and meat juice.
Keep an eye on the blade size. You want a blade big enough to cut through the size of the roast height you have. I guess if you are doing pastrami out of brisket, it’s the width of the roast that is your largest dimension, so you want to make sure that the table that slides left and right will accommodate the width of you pastrami. I love me some nice lean pastrami with lots of pepper.
cabelas.com has a couple on sale for $50 and $70 that are similar to what I have. Of course, they have other versions that cost up to $500 if you want to spend that much.
(my first post here but I was on the AO for years and years)