Quoted from toyotaboy:$40 each flipper mech
$40 each sling mech
$90 4-ball trough
$14 pair of lane guides
$15 1/2 x 24" x 48" plywood
$20 - set of playfield hangers
$20 - OPP driverboards
https://www.kickstarter.com/projects/507097900/open-pinball-project-open-source-pinball-hardware
$30 - 48v 7A power supply off ebay
$1 - 5v from usb
$1 usb cord
$3 - 6 posts for slings
$2 - bands for slings
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$356
All of this implies you are capable of cutting basic shapes out of wood for trough, shooter lane, and can print out a template for your layout of parts. Also that you already have a cabinet to put it in, and it has a shooter rod.
I'm reworking a new playfield layout, and I'm seeing how many things I can 3d print so I don't have to buy mech assemblies.
If your buying new, I'd put it closer to 5-600 bucks, but the best part is you can, buy it as you go, or save some by salvaging parts from a well worn populated playfield.
Even if you buy the complete flipper mech from Marco (50-80 bucks each), you still need bats and bushings, buttons, switches, screws and bolts.
As you work out the layout, other things to consider, switches, steel wire or banding for guides, inserts, sockets, bulbs, wire (lots of it and in different colors), pop bumper, drop target, spinner etc... as you design. I personally would add 2-3 pop bumpers in as standard for testing. The rest you can mock up with foam, but ultimately you'll want to test hitting and ejecting from a pop bumper to tune placement, and you can't do that without an actual bumper.
What's nice is you don't need to buy it all at once if your on a budget.
If you buy a populated playfield, you can get a great 'starter' set of little bits and pieces, but you might push it pretty close to new prices if the parts are worn and need to be rebuilt.
I'm keeping track of mine and will tally up when I do my cuts in the fall when I can get back to work on it. I'll share here.