I live in a rural town, no nearby craft store. Here's how I put my kit together.
Wal-Mart:
Bought one of every little bottle of acrylic craft paint they have. The selection is a lot less today with an emphasis on the big bottles. I did eventually buy big bottles of white and black paint.
A selection of cheap brushes in a smaller size, and a few broad stroke brushes for blackwash.
plastic shelving unit for storage
platic palettes
Can't get model brushes anymore, as they stopped carrying any model car or rocket supplies.
Also Pledge Floor Polish with Future for a blackwash additive, and PineSol for cleaning paint of minis.
Gallon storage bags to put palettes with paint in (they keep wet that way)
Ace Hardware:
Matte finish sealant and white primer.
Metal file for cleaning up flash and pliers.
light and magnifier on metal arm.
Visits to hobby supplies stores in the big city (Hobby Lobby, Michaels)
lots of small brushes
broad selection of acrylic paints for skin tones.
Lots of other things to paint, inch square blocks for terrains and flyers, inch wide circles for conditions, a woodern castle tower, treasure chests, etc.
At home:
Old glasses for water
Box to spray in
couple of old tables and chairs