We have built several. Depends on what you want to do. If you don't have much lift, just use a bilge pump for a boat (we use Atwood pumps if we can get them). They cost about $50 and will pump 1500+ GPH.
Float switch, you need a pump up (opposite of a sump pump). We get ours at Princess Auto.
Panels we have bought from Ebay, Canadian Tire and reputable solar dealers depending on size and $. Charge controllers, try Canadian Tire (amperage on the controller needs to be bigger than the panel).
Panel mounts we build our selves from angle iron.
Also you need an inline fuse from your automotive store between the battery and the pump. We use Marine style deep cycle batteries from wherever they are the cheapest per amp/hour.
Set up is
Panel > Charge Controller > Battery > Switch > Fuse > Pump
If you need more lift look at the Lorentz pumps (like a PS150 with control panel). We have also used the 12 or 24 volt sprayer pumps for higher lift/lower volume applications.