I have to agree with Nigel. The Chinese are selling so many useful electronic modules and such for next to nothing that using their stuff can save a load of work.
This is what my USB to TTL's look like. If you need flow control lines these will not work. They only have TX RX 5V and GND. The Tx line is 3.3V. They are Chinese but purchased on ebay from a seller in California. I was working on the miwi mesh net and wanted one for each of my test nodes. Thinking I paid $10 for 10 of them.