i think if it were me i would go about every 3 feet or so that way they would grow together, produse a nice wall but not be to crowded. but thats just my opinion.

The guy at Lowe's said every 12 feet but I thought that was too far... At every 3 feet that's a big cost difference. Will these grow together and look like an actual hedge, or are they just going to look like a bunch of bushes?

For a hedge effect, I planted mine 4 feet apart. I've read that 4 to 8 feet is optimal for them.