w Locked 27 Jan 2021 28 Jan 2021
You probably have to buy all the items from the shack in one go
It didnt work when i collected all the items one by one or going cumulative for specific number via second play through. Likely it's a buggy achievement, i could get it years after i completed the game because it wasn't triggering.
Here is what i did:
1) had enough coin to buy it all
2) went to supply shack and started buying from right to left in a single shopping (i don't know does direction matter)
then achievement unlocked moment i bought last item
or decrease patch to 811.3