I would suggest that if you think about buying a machine, do not even think about buying a lightweight one for about £50. If you progress, you will soon need a more complex machine.
Borrowing one will give you the opportunity to see if you like sewing and what sort of things you will make. Stating the blindingly obvious, heavy fabrics require a good motor, and IIRC a slow speed.
To practice on, look out for remnants, there might even be some on the Oxfam site, under household and fabrics.
You could practice sewing by hand and some hemming etc. If you have an Auntie who has stopped sewing for any reason, I would think they would be very pleased to let you have whatever sewing items you might need, like pins, needles etc. You might like to start a fresh thread (
) about starting sewing, as I am sure there are more expert people on here who could advise you.
Or with fleece, for instance, you could buy a cheap one in a Charity Shop that you know is too big, and alter it to fit you. You will no doubt learn by your mistakes.