Craigslist is great if you can work with used but you'll invest some time to score a bargain.
I did my camp last year from Home Depot. they put their stock cabinets on sale regularly at 20% off and the quality is decent. Just check the store every few weeks. They do it fairly often. We bought ours around Mid January last year. Spent around 1200 for 10 cabinets total. Kept it under 2 grand with counter, rewiring, new dishwasher (yep! a dishwasher at camp!) and built in microwave.
Some good pointers passed along, especially the ones about checking with remodeling contractors for (often free) used stuff and good deals at suppliers.
Almost everything inside my camp was gleaned from my job sites/suppliers over a year's time: Nice cabinets from a house we demolished; Same for the almost new 100A service; Kitchen counter and vanity top from a supplier's "bargain bin"; Barely used elec. water heater (someone switched to gas when they bought the house); Perfectly good toilet from a remodeling job I did; Kitchen sink/faucets from another job; Ceiling fans, slightly used; Doors/windows, same deals on used, or bargains on new stuff.
One 6 panel insulated steel entry door I scrounged from a dumpster, where some flood remediation was taking place. Nothing wrong with it, hadn't even been under water. And it came with a shiny brass knocker and peep hole already installed.
One of my farmer neighbors enjoys the knocker whenever he stops for a visit.