$150 would be money well spent. Just think. You can seal the sails up in there and know that they will stay clean and dry. I am building a trailer to carry six Sunfishes and enough 8" PVC to carry seven rigs. I know it will cost me, but I don't think anything else will work as well. I also would prefer to store all my Sunfish boats and gear on one trailer. I can then shrink wrap the whole thing or simply tarp it for the winter. It would be best if you had both the spar bag and the PVC tube. If you are looking for cheaper options, I'd definitely invest in a $50 sail and spar bag. If you can store the spar bag indoors, you could probably get buy with just this. A couple of bungee cords will hold it down on the trailer. Bungee cords will cause some wear and damage to the sails, so pad the area you bungee well.