I usually buy used so here's what I can tell you.
The lowest level machine you can get is the PE-150, very basic,used runs around $150. It's the same machine no matter what brand you buy. These are very dependable machines and have a good resale value. Takes cards and PED Basic software.
I own both the Bernina 600 and 650. These are embroidery only, will take cards and PED Basic software. Also very basic machines, the difference between the two is there are more patterns on the 650. Used you shouldn't pay more than $300 for the 600 and $350 for the 650, unless they are including bunches of accessories and/or software. It takes cards and PED Basic software. These also are dependable machines with good resale value.
I owned a Brother 8500D, which I paid $2800 for new. It was a great machine, no problems whatsoever, a combo sewing/embroidery machine. I never sewed on it. It takes cards and PED Basic software. I owned it for 3 years and sold it for $1500, including the PED Basic software
My newer machine is a Brother Innovis 4000D, which is also a combo machine. I paid $5000 for it nearly 4 years ago. I love it, it works great, but if I had it to do all over again, I would look for a machine that is not a combo. I will probably never sew on it, when I sew I always have the embroidery machine going at the same time. This machine takes cards, PED Basic software, and has a USB port.
If you find a machine that you are interested in, go to
http://sewing.patternreview.com/ and look for embroidery machine reviews and see what others have to say about it. This is a great site to get reviews on embroidery machines, sewing machines, and sergers.