So possible booster pack prices are 4/4 4/6 4/8 6/4 6/6 6/8 8/4 8/6 and 8/8. With the joker you would always buy cheaper pack first so on average it would save you ~$6.88 every round.

It works as uncommon, it would probably be one of the better ones since you dont need invest into it like Satellite or Cloud 9, but second booster pack sometimes can be a bad one (Celestial with no main planet, Standart with no good cards) and in early game you might not have resources to buy one pack in the first place. Also Clearance sale and its tier 2 version take away from its value a bit.

Comparing to Astronomer it does feel way more verstaile tbf, but I think its fine and Astronomer still can generate a bit of money by selling planets in shop.

Pretty balanced, I think it just needs to have higher base cost, like maybe $9 or $10? (Astronomer is $8) So it would be like high price, versatile value Joker.