The following seem to be the big names in electronic component supply:
www.mcmelectronics.com
www.digikey.com
www.mouser.com
www.jameco.com
What are the relative merits of each for a small time parts ordered
(<$20)?
My analysis below is sometimes distorted by deep history (going back to
the 70's or earlier in a couple of cases). But here it is:
MCM is great for repair tools, repair parts for consumer stuff,
etc.They are somehow corporately tied to Newark now which is an
"old-line" industrial catalog house. I do not understand how the
"In-One" companies interoperate (they seem to not interoperate for the
most part!)
Digikey and Mouser are not perfectly interchangeable but both have lots
of stuff in stock and pretty good (Mouser) to exceptional (Digikey) web
ordering interfaces. Both have really extensive (but not identical)
selection of semis, passives, cabinets, tools, etc. Both can get you
not-in-stock stuff without great difficulty (but with minimum
quantities).
Jameco was traditionally a hobbyist supplier. Several steps up from say
Poly-Paks but several steps down from the big catalog houses. Always
had a good selection of hobbyist-oriented semis, medium to poor
selection of passives. They have obviously been angling towards
becoming more full-line and stocking like Digikey et al but have only
made minor baby steps in that direction. What they do stock is often
cheap (and if you look at the date codes it may be a few decades old
too...) They still have very poor selection of passives, almost zero
precision stuff, etc. For a while they had a very good selection of
surplus power supplies, now they have a very good selection of new
switchers.
Tim.