Forming a Delaware C Corp is on the order of $500 using an online service (including all the post formation docs such as founder stock agreements, etc.) and takes just a few days. As Mike mentioned, you'd then need to register in your home state and start paying corporate taxes in a few months.
The advantage of not filing now is that you still have the $1200-$1300+ in your pocket. The downside is that you can't really do anything that normally requires equity... e.g,. getting an advisor on board, investment, etc. And, of course, you will have personal liability so if your MVP kills somebody's pet gerbil, there's no entity to protect you.
Would definitely *NOT* try to revive a musty inactive corporation. Who knows what liabilities, shareholder rights, etc. may be buried under all the dust.