Window Shopper
Window Shopper tracks the items_purchased stat and only needs one shop purchase to clear. The shop in question isn't specified further in the achievement data, but MythFall's documented Premium Shop sells items directly with either Robux or Astral Shards (see the Astral Shards currency page) - if items_purchased counts any shop transaction, even a cheap Gold-priced item could clear this achievement.
At 15 Astral Shards for one purchase, it matches Apprentice Smith as the highest per-action reward of any documented achievement, and notably pays out in the same currency (Astral Shards) that the shop itself sells - effectively refunding part of a shopper's spend the first time they buy anything.
Details
FAQ
How do you unlock Window Shopper in MythFall?
Buy any one item from the shop - the items_purchased stat only needs to reach 1. The achievement data doesn't specify whether this must be a Gold or Astral Shard purchase, so either likely counts.
What does Window Shopper reward?
15 Astral Shards, MythFall's premium currency - the same currency the Premium Shop itself sells items for, effectively handing back a small premium-currency rebate on your first purchase.
Is Window Shopper worth doing early?
Since it only takes one purchase and pays a relatively high 15 Shards, it's an efficient early achievement to knock out alongside Apprentice Smith - both are one-time actions that pay more than any single-tier Combat kill-count achievement below War Veteran.
Other achievements
Source-checked
Extracted directly from Mythfall client data. The specific shop (Premium Shop vs. an in-world vendor) is not specified in the source data and is noted as an open question. updated · GuideDex staff. Report a correction.