I'm getting a root canal and a build up, but i can't afford the crown yet. what shouldn't i eat after i get the build up? what's recovery like?

Anything really hard: The need for the crown varies a bit depending on which tooth is involved, the state of your occlusion, and how extensively restored the tooth is after the root canal but in any case avoid chewing ice, frozen candy bars, or chomping hard candy for the best outcome. Often, it's an accidental encounter with a small stone or bone chip that can fracture a post-root canal tooth without a crown.

Caution: You've invested a lot of time and money to have the RCT and the buildup. It would be a shame to bite down on the tooth, have it fracture and then need to have it extracted. That does not always happen but the risk will ALWAYS be there until you get a permanent crown. Other than not biting down on anything hard until you get the crown is all you can do. See if you can work something out.

Root canal: Unless sealed properly at both ends root canal may be in jeopardy. Talk to Dentist about a payment plan that will expedite placement of final restoration. Important to place crown ASAP. In the meantime avoid anything that may damage temporary restoration such as gum, ice, hard candy, pizza crust, crusty bread bagels, etc.

Root canal therapy: Teeth that need root canal therapy are usually broken down and do not have much solid tooth structure remaining. They also become brittle. Avoid any hard foods in that area. The build-up will not hold up for long. You need to make that crown a financial priority, or run the risk of tooth fracture and loss of the tooth.