Sewing machines seem to be less expensive than they used to be, comparatively. If you can possibly try one before buying, I would do so. I have used various economy machines when teaching sewing classes, some of the foot pedals are not very sensitive so can suddenly jerk into action at a faster speed than you would like. The stitching on all the machines was fine, whatever the make.
The new tiny machines at around £50 are a bit limiting, although very pretty!
I love my computerised Brother, but repairs to computerised machines are prohibitive, and yes, they are heavy. Any machine can be used with standard needles, but the bobbins can vary, even from the same make.