Affordable, decent quality items so I never feel guilty spending money on items I didn't intend on prior to my trip. As I live 50 minutes away, I always make a list online (and pull up on my phone) to make the trip worth while, and so I don't forget what I'm going for -always get distracted by cool items.
Definitely bring your reusable bags to pack up the items you buy. You can also buy Ikea reusable bags for about 50ยข/PC at checkout. Theyre awesome- made out of that blue tarp material so they're durable.Ikea doesn't provide any kind of free bags for your purchases.
I could go on and on with tips about shopping/eating etc. at Ikea but that'd take the mystery out of your first visit there!