Hey... when performing ID... what if a spectator sprinkles flour or talc in the air... surely they'll see how the trick is done?
Oh, and I have some money-saving tips:

Don't waste money on expensive playing cards... make your own by collecting cereal boxes. Cut the boxes down to poker card size and ink-in the pips with red and black pens.

Don't spend lots of money on things like magicians' wax. Heck no! Just go to your local GP surgery and ask if anyone is due for an ear syringing that day. If the answer is yes, get a sieve from Wilko and secretly place it over the drain outside the surgery where the sink pipe is. It will catch the wax for you. In this state, it's great as soft wax. But you can put it in the freezer and it goes harder.

DO NOT throw your cards away when they get oily and greasy... cover them with passatta and mozzarella and grill them for 5 mins. You won't be able to use them, but hey—you'll get a pizza the action.

Forget expensive IT and IET... you can grow your own! All you need to do is go to your local garden centre and ask for some easy to grow, fast growing seeds, I prefer onions. Here's the clever bit... plant the seeds and when you see a chute appear, quickly cut the chute off and swap it with a bit of IT or IET. If you are sneaky, the seed won't know that it used to be an onion plant, and will continue to grow as an IET plant. If you're lucky, you could easy get three or four plants growing at once.

Want an inexpensive magic wand? Well, here's how! Go to your local burger restaurant and get a drinking straw. Also, go to the DIY shop and ask for paint pot samples of black and white paint. Now for the sneaky part... On your way home, stop off at a quarry or other clay-ridden area. Fill the drinking straw with clay and take it home and bake in the oven. Now, when fully baked, paint the straw with your free black paint. Then, when dry, dip each end in the white paint. VOILA!

Want to do some cool coin magic? Well, here's a way to multiply your money without buying expense coin magic books, dvds or gimmicks... all you need to do is build yourself a time machine, but small enough to fit inside a piggy bank. Set it to recurrently revert back in time by 10 seconds.
Then all you need do is borrow a £2 coin. Put it in the piggy bank, and take it straight out. 10 seconds later, there will be another £2 coin in there!
Now... the next one is tricky... because you left it 10 seconds exactly, in 10 seconds time, you would have taken out the first coin which has already reappeared, so you need to take it out exactly 9.99 seconds after the second one. Then, just subtract a 1/100th of a second each time. In no time at all, you will have a pile of coins!
Of course, when it gets too small a timespan, just start over by putting another coin in! (Remember to give the £2 back to who you borrowed it off, or they will put a curse on you and your bum will go all spotty or somefink, so I heard).
I've not tried these yet, but surely they will work.