Ok I am just getting into biking and I have not conquered the mechanical side of this yet. I blew a spoke a few weeks back and it was fixed for me and all seemed fine. That was over 300 miles ago. Now two days ago I went to ride and my tire was flat, so fine I replaced it. Next morning I rode out and midway through my 8.5 mile commute, it had slowly gone down again. So that night I replace it again. This morning same thing slowly went down to flat again. 3 days , three different tube bought at 3 different places.

Things I have done:

I am careful not to pinch the tube.

I have checked the tubes and there are pin hole leaks in them.

I checked the tire itself to see if there was something poking through and found a very small thing yesterday and removed it but all else seems smooth and that did not help this morning.

I checked the rim tape and that is fine.

The holes do seem to be on the top of the tube.

What do I do? I don't really have much money at all right now and a new tire (let alone a rim) would be pushing finances. I have a low end Schwinn road bike $400, but please no buy new everything posts as I can not afford it. I ride 200 miles a week on this bike and I am at a loss.

Thanks for any help.