A pet exercise pen works great and so do extra-large dog crates or NIC condos that you can make yourself. It depends on how much space you have. There is a thread on this forum called "cages you've made 2014" (plus other years), that you can see pictures of peoples cages/hutches.
By the way, it sounds like you will be a first-time bunny owner so I want to let you in on some information I wish I had known before I got my first bunnies. If you are getting two rabbits who are babies, they may get along fine at first, but when they start reaching sexual maturity at 3 or 4 months and the hormones kick in, they may start to fight and you will have to separate them. I had that problem and even though I had them neutered, I was not able to bond them afterward. They just kept fighting. You also need to be aware that sometimes whoever you get your rabbits from may be wrong about whether they are male or female and you can end up with a surprise litter.
If you are experienced with rabbits and know what you are doing, then ignore my advice here. If you want more information on bonding rabbits, etc., just ask. There are a lot of knowledgeable people on this forum happy to help.