Re: LED samples?
most manufacturers and some distruibutors do sample their optical parts.
Its mostly determined by value. Most leds are cheap maybe 10-25 censt so samples of them are pretty easy. If anything lists for more than $5 dollars though you will have a harder time getting them, so you may have to buy.
Mouser.com
digi-key.com
are two I know of for sure.
If you dont see samples at a mfg site you can always try their distrubuitor or email their sales office directly.