Of course most OA journals are new and need name recognition. But those like Plos ONE, Nature MSB are HIGH impact journals.

Funders like Wellcome Trust and NIH are more than willing to pay the upfront publishing fees. Are you paying out of your own pocket :?
Low cost OA journals are there but I can't think of an example now. In the long run, OA journals can cost 1/10 of traditional journals. The economics are still being worked out. These are early days, and as I said, do it when it's feasible for you.