| Azothath |
as RPGs are an advanced version of the child's game, "Let's Pretend", there are a lot of things you can do with ingenuity and creativity. Some are more reasonable than others (there's usually some rules lawyering), so we shall stick to the more reasonable and successful. Let's try some sensible things that cost less than 200gp (which keeps it in the range of reasonable).
As always your mileage may vary(YMMV) as most thing lie within the GM's gray area. That's not a bad thing. The printed material can only cover so much and we are getting creative.
In many cases tricks rely on Skill checks to force another skill check. The trick is most NPCs/players make assumptions and don't make that second skill check to discover the ruse. Often there is a bit of rule-lawyering and I'm asking people to keep the rules stretch tight and reasonable (an 80% GM approval rating). Combining a simple trick with a bit of spellcasting gives the trick some punch in the game.
Examples;
Name(trick). Description.
Problems:
Cost:
Cheaply detect Invisibility. Powder costs a copper. Use contrasting color sand or dirt, there's lots of it and it's free. If you're indoors (especially in a bar) use liquids like water or throw your drinking buddy's drink. A freshly mopped floor also works, use soap for a little slip. Don't get caught loosening the stairs in your inn.
Problems: easy to spot and get around (sometimes). Circumstantial. At worst +4 crcm Percp versus their Stealth.
Cost: 0gp
Sham or Fake magic items. Don't try to stop Slight of Hand or the Steal CM – provide the targets! Paint some some nice sticks and attach sparkly bits or some feathers and wear them openly. You'll need an applicable skill check or support the arts and pay an NPC to do it for you. You now have bogus wands for thieves to steal rather than your real wands. You can do this for a myriad of items.
Hold one and cast magic missile and pretend it's a wand! They don't know magic! If they do you just spotted the magic user.
Problems: Yes it won't work if they use Detect Magic and concentrate for 2+ rounds or make a good Appraise check.
Cost: $0.1 to $10 and a skill check.
Ioun Stone Suprise or The Sign of BAM. {see - you read that didn't you} Paint a burned out ioun stone. Again you'll need an appropriate craft skill or have to support the arts. Paint some tiny writing on it (Goggles of Minute Seeing, Lens of Detection) which really doesn't require any skill check. Cast Explosive Runes. Optionally spend 50gp and cast Continual Flame(heightened) on it. OMG! an Emerald Ellipsoid ioun stone! It's got something on it... it sez *BAM!*.
Works on fine faux jewerlry("Property of *BAM!*"), faux gold rings("...one ring to *BAM!* them")... and of course signs you plant around your campsite ("*BAM!* 30mi")... You get the idea. Yes, the tiny ones are hard to read unless you look, which makes it a perfect stealth trap just waiting to be sprung by someone closely examining the item (like Mr. Wizard with no Det Trap skill), just make sure it looks like a magic item as it will detect as magical.
Problem: Painting & tiny writing. Cont Flm may make it hard to read or provide lighting.... May take awhile to be sprung but a good revenge on your looter.
Cost: $25 +$1(faux treatment) for 10 to 20 items, skill check. Exp Rx 3@5 (that's 3rd level spell cast at 5th level).
Hand Buzzers. Okay - simply this - Glyph of Warding on a ring. Yes - it seems nonsensical until you realize that a finger enters a ring when you put it on (aka the warded area). ohhh...! again it will detect as magical. Trying this on armor and such is a further stretch as rings are tiny portals. Underwear could work but they do tear. So keep the rules lawyering tight! Use cheap plated rings or paint them gold to keep your cost down, or protect your own rings.
Problems: Read Magic with Know Arcana DC 13 which is pretty easy. Luckily it's unexpected and fine sized. Casting this on something that can unclasp or open will probably set off the spell.
Cost: $1 +$200 for the Glyph 3@5.