Hey just wanna hop in and say I was having this issue too.
I have a fix though.
make sure the last meditation point you were in ISNT the one in the basement of Pyloons.
go to the one outside of town and then buy all the merchandise. Achievement should pop then.
for some reason the meditation point in Pyloons glitches things like this among other things.
Unfortunately I have already bought everything and cant go back, I tried reloading from a different meditation point while having everything bought still no luck.
go to zee and purchase something. I did that after traveling planets and meditation points and this is when it popped for me.
