OMAS components were weight-weenie replacements for heavier high-end components, e.g. aluminum stem bolts to replace the steel bolts in your Cinelli stem, aluminum pivot bolts for your Campagnolo derailleur, etc. Later they started making their own bottom brackets and headsets and such. I'm not aware of any OMAS components that could be termed "budget" or "low-end."

OMAS, main