This isn't the right FT forum or even the right website for this kind of question. Mods may move it since it has nothing to do with earning miles/points.

Split your utility bills into small increments. Some companies allow payments of $.01.

Other ideas (most are widely known and discussed at fatwallet & elsewhere) ...
- Amazon GC, as low as $.15 -- not sure if this still works
- Charitable donations - some as low as $1.00
- buy songs or apps on iTunes for $.99 each

Not online but other ways ..
- pump 1 cent gas
- 1 cent bulk food at grocery store (SCO to avoid scrutiny)


I'm sure if you search on the proper forum you'll see other interesting ideas. FWIW, some people may frown on this idea because it theoretically accelerates the demise of reward checking accounts or leads to lower rates.