Welcome to the community! I have only been playing Splinterlands for three weeks now, but I really love it.

If you don't have much money, then have a think about renting cards instead. They don't cost a lot, and you can normally recover more DEC from higher level games to completely off-set the cost. I wrote an article about it the other day (@sbenbow/renting-cards-best-thing-i-have-done-newbie) but I really would recommend giving it a go. It moved me from Bronze II to Silver III and I recovered the total rental cost of the cards within a 36 hours.