This year I put 5 gallon water bottles with the bottoms cut off and no cap over my tomato and pepper plants. These are bottles that are meant to head for recycling as they are no longer usable for bottled water customers. Leaking, discolored, too old.
I was able to put these heat loving plants in 3 weeks early, and they thrived!!! I placed the plant support stakes in at planting time, and set the bottles down over top, with the stake sticking out of the bottle top opening. They didn't budge during recent heavy storms. After they come off, they are easily stored stacked over a tall plant stake until next year.
Check with you local bottled water company, and see if they will sell these bottles to you for a nominal amount.