Identifying replacement bearings for installed heater fan motor
The way to find different bearings is by the size bb1023 crosses to a double sealed 6.35 x22 x7  mm bearing 
Mr627zz is the same id/od and 1/4” thick so it is slightly thicker and may work under 5 bucks. Looking at the bearing specs I would give it a try. I cross bearings for motors all the time, I can tell you a timkin or sky bearing in some cases is worth the extra but in a light duty motor like a fan I would save a few $ 
Mr627-2rs
Mr627zz 
I thought I typed in the wrong size after double checking my answer but I just typed the size wrong in the answer corrected.