I have a fairly new Bernina without stitch regulator and I can do nice FMQ.....but I can also do nice FMQ on a 1904 treadle by 0 out the stitch length, a 1950 clone Singer Model 15, and maybe my Featherweight (haven't tried her). You can see there are many options available without spending big dollars.
A little tip, some newer machines that have the bigger needle hole for zigzag stitch are sometimes not as cooperative with FMQ but again, you usually can buy a plate with the straight st. stitch hole.
Hope this is helpful