Buy a name brand, like H&R or Eibach. Or go to a quality retailer like MM. At one inch or more (maybe on the 3/4 too) you will find spacers have their own lugs. That's because you can only use a spacer so deep before you end up leaving too few threads for the lugnuts to hold.
Plenty of guys on this site have bought the no name spacers off eBay and have had good luck. But this is something I would happily spend the extra $50 to know I have a big company to sue should something happen (J/K, I'm thinking more of quality here). If you do go the cheapo route, make sure you get hub centric spacers. They're the one's with a raised rim around the inside (just like your hubs). Run a search on hubcentric versus lugcentric and you will get plenty on this.
After you install em, run for 50 miles, then retorque.
Oh, and measure before you buy. It's pretty easy to do. Just take a straightedge against the outside of the tire. Then measure from that surface to the inside of your quarter panel. Leave yourself 1/4 inch clearance, and you are good to go.
Oh ya, and if you go 1" or smaller spacer, your wheel will need to have openings where the primary lugs and nuts will nest into when you mount it all up.
