Japanese Maples, like all other slooooow growing plants (i.e. Sago Palms) are costly because of all the care and feeding it gets while it grows until it is saleable. I found a generic "Red Maple" at of all places, Aldi. It was $9.99 and about 2 ft tall. It is now the size of a $50 tree 10 years later! Since I don't know what it is, I am having trouble determining if it is a weeping variety or not. At first I thought it was and started to train it as such. But watching the branches grow I wasn't sure so I removed the stakes. Now it wants to grow straight up! I's like it knows I don't know what i am doing!
I think the most important thing is to know which JM's grow best in your area. Houston has 4-5 that are recommended. We get some pretty intense heat and all JMs have to grow in the shade. The Coral Bark JM however can take some dappled sun I have found but everything I have read says "shade". My Shishigishira cant take no sun at all even though I found it sitting in the sun! I have 6, I am pushing the zone with one or two for sure. Then will you grow in a pot or in the ground? Full growth or bonsai? All mine are in pots as there are too many tree roots in the yard now that would take water away from anything planted in the ground. First year (or 2, depending) I keep them in their original nursery pot. I will be upgrading pots when needed letting it grow as large as it can. Lastly, what shape do you want? i am no help there since I suck a pruning. But looking at the photos there is one with two main trunks. I don't think that would do well as a full grown tree. It could easily split when it matures in 30-40 years from now.
If you were to bonsai it with lots of pruning all it's life, this may be the one for you. Did that help???