Those online courses sound convenient, but expensive and at 4-days, they seem overly long and drawn out. I could see it costing that much if maybe it was for the OSHA 30 or HAZWOPER courses.
I took the OSHA 10 course in a one day seminar about 4-years ago for about $150.00 and that included coffee and donuts for the morning break.
It does seem like OSHA 10 certification is now becoming the minimum required for subcontractors and employees just to set foot on some construction jobsites.