I'm waiting on my order on 4x RideNow TPU tubes from AliExpress, for under $30 USD which I bought on sale. Much cheaper than a single Tubolito tube. I bought my first order of RideNow tubes a few months ago and have been running them on 700x30c tires. Overall the experience has been very positive. I've been using these tires on both fast group rides and hill climbing and when paired with lightweight clinchers you can really feel the difference in weight. In fact I'm also running 28c tubeless tires on another wheelset and I think I prefer the clincher + RideNow tubes since they weigh less and my clincher sidewalls are just more supple. Once I get my 2nd order of TPU tubes, I'll use one of them as a spare in my saddle bag to cut weight from my spare latex tube.