this is such a personal choice, My advice would to be buy the best quality machine you can find, which may not be the cheapest you can find. If you are learning and you have a machine that is fussy or does not sew well, it will frustrate you and take the joy out of learning - and could turn you off from sewing. I'd buy from a dealer, they are your support system as you have questions/problems/need help.
my own journey started with a 1940 black singer, "aka, the beast", then a kenmore (20 years and still going strong) , then a Janome MC6500 and a Bernina 440. I loved them all, but as my skill grew I wanted more flexibility in the machine to do more things, these machines were over a 25 year period (oh my gosh, am I that old, lol!) good luck with your purchase and enjoy for learning journey.