Home made scopes - lenses and mirrors?? Which is best?

Hello,

I have heard of many who make their own telescopes, reflecting and refracting
alike.. I know enough physics to do it right but I dont know where I can buy
lenses and mirrors for this. If anyone knows good sources (esp for custom sized
ones) I'd appreciate it... Also, which do you folks find give higher quality
images? Assuming equaly stable platforms and eye pieces which looses more
light, etc?

Thanks