Selling older cards to upgrade more?

Some advice, I have slowly been trying to get back into splinterlands but am unsure what to buy. I have gone and checked a few of my cards and I have found that I own an alpha dragon welp and it is worth around $50 and I have another card worth $10.

Do you think it might be worth selling these and buying a few cheaper cards. or should I keep these and just push to try and earn more reward cards?

As an older player, what would you do?

?