are you forced to buy galaxy points, so you can remove planets? i have like 30 planets i scanned, and i cant scan for anymore cuse i am to small to get good scanners, and the money needed to colonize one is over 1mil

Star Chart Purgers are available via GP, your planetary artifact production (1000AP), or by doing a repeatable mission later in the game. They cost 5 energy to use and will clear a planet from your database.

As for the credit cost to colonize a planet, talk to your legion mates or friends who play the game. Safe bet someone will loan you a couple Kurenite.

there is an artifact that purge planets

You could also try to sell some artifacts to gain credits. your options include the trade board here (sub board of the galaxy pub) or one of the facebook groups dedicated to trade. There is a post here giving prices for many artifacts. Just ask for KU(renite)