Note:
If you're looking for the cheaper cardboard for custom tiles solution thread, that's here or the thread on
cheap custom dice rolling cup solution that's here )
So I started out using custom Hero Quest figures nearly a half a year ago (using those polymer Reaper Bones miniatures), colored with Formula P3 paints purchased from hobby stores. I never bothered with Army Painter... but the citadel paints I had from ages ago dried up super fast (the containers weren't quite air tight in the late 90's I guess... the "snap caps" are much better than the old screw type bottles).
When painting minis, I mainly was about quantity... painting lots of small minis (intended for play) or covering large areas evenly with the paint, as opposed to doing fine detail on single figures for display.
So I blew a lot of money on these things over the years prior, and I know people suggest diluting or thinning it out with water, etc. but I was mostly doing things in flat or solid colors, so I realized, far too late, that it's much better to just use those bigger containers of acrylic paint found at places like Walmart or Hobby Lobby (primarily AppleBarrel and FolkArt). You get a wide variety, lots of paint, pretty cheap and while they're slightly less satisfying than the pro stuff, they get the job done... AND I discovered DecoArt produces this "Duraclear Satin" varnish coat, which is fantastic. It blew away the professional vallejo satin varnish that cost way more (again from the game store). DecoArt also makes this "Americana" series of gloss enamels that I've had pretty good luck with so far.
I purchased some of those little "snap top" clear plastic containers (the ones with many little cylinders all linked together in a chain) for paint mixing, because I previously had the problem of mixed paints drying out (I tried putting them in empty plastic gum tumblers or on an artist's palette with plastic wrap over it but that only lasts a little while).
I don't prime the Bones minis, just dip them in boiling water (straightens out any bent parts and cleans off any excess oil from the factory). Air dry, and then slap the paint on and put them on the drying surface (aluminum foil, usually).
So I'm now sold on using these paints. I will paint a figure in matte acrylics, and then put a thin coat of Duraclear to give it a nice varnish that isn't tacky to the touch (the vallejo satin was still tacky after a week) and stiffens up the polymer a little bit on the Bones minis. Other times I have mixed a "gloss" paint with a "matte" and come up with a pretty nice looking in between finish (might not hold up to oily gamer hands though). I use a set of basic Plaid brushes to apply the paint and leave to air dry 20 mins to an hour. Clean the brushes right away with tap water and dish soap. Done!
Now on the day I decide to start painting "detailed" minis and actually using washes and things, I may go looking for other solutions, but for now, this gets the job done. The varnish too was a game changer... I had used paints to fix up some damaged toys, and the paints would chip, or were tacky, had rough spots, or didn't blend well with the old paint job, and the varnish fixed that right up (especially when the joints need to be movable). The only downside is that if you glop it on (and don't "dry brush" it out of the various crevices) you can lose some detail and end up with a "wet" looking figure.
I've gotten a few free Master Paint (MSP) samples from Reaper with my orders and they worked out pretty well... just a thin layer and then apply the varnish when dry.
The minis I've painted have sat out for days while I'm working on them, but generally I store them in plastic tackle boxes, so they're not collecting dust. But with the varnish coat they should be easy to clean with a little tap water and a gentle towel.