My Rolleiflex came with a Leicatime strap that the previous owner had purchased. I'm very happy with it. It has the Rollei scissor clips, so it's easy to remove. It's not nearly as well-padded as the OpTech strap, but it's still quite comfortable.
$210 seems like an awful lot, though. I believe it's possible to have scissor clips riveted to the OpTech straps, which might be another option for you.