Also, some things are more expensive over here - my 160gsm cardstock costs 13 Euros per 250 sheets (that's roughly $ 16, couldn't get it cheaper around here), foamcore is more expensive (see other thread) at 2.50 Euros/sheet (and you will usually have a hard time getting any color but white), as are good non-bleeding markers.

For a masterboard, I'd again recommend 3mm (0.12'') MDF as a mounting base, since it doesn't warp and is more durable than foamcore, and slightly cheaper as well if you buy it at a regular hardware store like OBI.

You should go to a refill shop (or use refill ink yourself) for the ink, i have a large (double space) HP 3 in 1 cartridge, but refilling it costs me just about 12 Euros (plus 9 Euros for the black one), and one refill got me all the way through Firstlight plus Retrofit plus my whole Wormhole separatist fleet including a command tray. Not too bad, and I don't dare to guess what it would have cost me had I bought fresh cartridges.

Adding up:
+ MDF (roughly € 3,- for that size)
+ Refill for, say 1x black and 2x color Cartridge (or the other way around if you print more grey stuff, so that's about € 35,-) - that's enough to print everything you'll ever need for that dungeon, crammed with props, but it depends on your printer. Mine is adorably ink-saving.
+ your choice of UHU office pen or twist&glue bottle (€ 2,-)
+ a cheap pack of gluesticks (€ 2,-)
+ a typical pack of 250 sheets 160gsm printer cardstock (€ 13,-), but you can use standard paper for the ground tiles
+ a pack of black or brown markers from a discounter (€ 2,-)
+ a pack of knife blades (€ 1,-)
+ paperclips or pins, depending on your dungeon (€ 1,-)
+ WWG Set ($ 17 = € 15,-)

So that's € 75,- with a lot of stuff, and half of it is the ink. Probaby your paper/cardstock and ink will last for two sets, but let's say we calculated a worst-case scenario and your printer is a bitch.

If you feel adventurous, add € 10,- for a spray glue can for the masterboard, but you could also apply a thin sheet of white glue with a painter's roll (the ones made of foam, not the shaggy ones), which is probably cheaper.