Just my two cents
I have a very bare bones basic machine - a 13yo Kenmore which I use for everything - sewing, repairing, quilts, clothes, costumes, bags - you name it. My personal recommendation is that any machine should (with the right attachments) do whatever you need unless you need fancy stitches, or embroidered designs. If you are essentially planning to sew pieces of fabric together and occasionally need a decorative stitch any new basic level machine at Target or Walmart should work. You can literally spend thousands of dollars on souped up machines that will do all kinds of funky stuff but the question is do you need it?
I would say to start out if you're not sure how much you'll use it and for what - your best bet is to go to St. Vincent de Paul or Goodwill and buy a used machine for $15. So long as the machine works - you should still be able to get parts / attachments (especially Kenmores). Many a good machine has been donated when a parent stops sewing or dies because the children don't sew. If it's older, the most you might need to do to get it in fine order is to have it tuned up (usually $25-$35) - they recommend you do this every so many years - I'm overdue I've never had my serviced. Any local sewing / fabric store should be able to direct you to a service person. My local Jo Ann stores in two states offered a service where they advertised a drop date and you could bring your machine in and the service guy would pick it up, and bring it back w/in a week serviced. Made it easy. With a used machine - you can also find out what you really need / want in a machine before you invest in an expensive one.
Attachments and feet can often be bought at the local sewing store from other manufacturers for different machines. If you bring in a foot from the machine you buy - and show the store personnel how it attaches to the shank you should be able to find a different brand foot that works on your machine. I've bought at least 3 different brand feet (non-Kenmore) for my Kenmore machine that work fine (often fancy feet for quilting and sewing that Kenmore just didn't make for my machine).
The other cool thing about an older machine is that overall they're tougher. I had an old black Singer (in the cabinet electric) that was tough as nails. I'm so sorry I let my parents sell it after they bought my existing machine for me. That Singer could punch holes in metal - it sewed through multiple layers of leather just like it was butter. My newer machine isn't quite as tough. It squawks when I ask it to sew through 10 layers of fabric. It's great for every day but not so good for some of my more recent attempts at foam padded laptop cases and stabilizer reinforced bags.