Japanese maples sources
The picture is of a barely discernible "Butterfly" japanese maple (jm). This is one of the most easily recognizable jms with bluish-green leaves with a tracing of white on the leaf edges. It's a bad photo taken in the morning direct light with me ducking under the lath shade which keep the small maples from leaf burn. I bought about 15 little grafted jms from Worldplants and stuck them in my now defunct vegetable garden nursery. I've given up trying to grow vegetables with ground hog, deer and rabbit predation but as you can see the numerous cilantro seeds have sprouted around the jms despite my lack of care.
If you're interested in collecting japanese maples cheaply, Worldplants is probably the best nursery to buy them from. The 1 year grafted maples are very reasonable and they pack the plants very well for USPS priority shipping. I haven't lost a single plant from them even shipping the plants from Oregon to New Jersey. During their busy season in Spring you may have to wait a few weeks for them to ship but it's well worth the wait. Here's their website: http://www.worldplants.com/mapleintro.htm
A good site to look at all the different cultivars of Japanese maples is Mountain Maples. Click on Cultivars A-Z. Here's their website:
Their prices are a bit out of my range but their trees are bigger and I've heard good things about them.
If you're on the East coast J. Herter, North Carolina and Wildwood maples, Virginia are two sources. I've ordered from J. Herter and have had no problems with them and they ship very quickly by USPS priority mail. Herter also sells extensively on Ebay so you may be able to get a bargain. Again Wildwood is a little out of my price range as I want to collect many different cultivars. Here are their websites:
http://www.japanesemaple.net/japanesemaple.htm J. Herter
I haven't tried Eastwoods Nursery but it seems like an interesting site.
If you really get interested in the different cultivars, the bible of Japanese Maples is a book by J. D. Vetrees. I have the second edition which I had to buy used from Alibris books since it's out of print but some say is better than the third edition. Either one is a must if you are seriously contemplating collecting these interesting trees. Amazon has the third edition for about $35.