Different item types have different ilvl-requirements for the same affixes. If another player is in town, the shopping window won't update, even though you are exiting in and out of town. After ilvl 25 vendors only sell magic items and no longer normal or socketed quality. This means that A1 and A2 normal always only sell normal / socketed items. Furthermore, vendors sell normal and socketed items up until ilvl 25+ (clvl 20+). This isn't always true though, in normal difficulty there is a cap of ilvls being shopped for all separate acts. This means that if you are characterlevel 10, items will be itemlvl 15, if you are characterlevel 15, itemlvl will be 20 and so on. The ilvl (itemlevel) of items presented is clvl (characterlevel) + 5. End-Game Items Worth shopping (Including Orb-guide).If you are looking for a gold find guide, you can find my goldfind barb (most efficient source of gold in game) here:

The holy trinity - shopping, crafting, gambling. You use in-game gold to shop from regular NPCs, Vendors, in all acts. Shopping in Project Diablo 2 is another tool to use to buy crafting material, some early/mid-game items, prebuff gear and LLD-items (low level duels).

Project diablo 2 items for sale