The leading candidates will be the mxr as mentioned above- although I wouldn't describe it as clean per se, more growly.
The ebs - new around £100 so s/h should be £60-£70. less growly than the mxr, and what I would call clean
The dod octoplus- highly underrated pedal. The only octave I have found that gives you a tone control for the effected octave. Should be found for around £40 ish.
Hth