Re: Identification and or Dating For worth. I want to buy one of them
The first horn is a student model introduced in 1997, Nothing remarkable about it as far as student horns go. It's not one of the dreaded "Mexi-Conns." Probably worth a few hundred at most.
The Second is not a Perfacktone. It is a Conn New Wonder tenor from the 1920s. The "LP" means that it is a low pitch horn, playable to modern tuning. High pitch horns are not playable to modern tuning. That particular horn has the "Artist" finish, with silver plating, really nice engraving, and burnishing of the bell design. If we assume you missed a "1" in the serial number, it was produced in 1925. Those are very good sounding horns, but quite demanding of the player compared to modern horns. Its value is probably above $2500.00 depending on condition.
The third is a nickel-plated Perfacktone stencil horn made by Martin in the 1920s. Stencil horns were horns rebranded by merchandisers. The soldered-on beveled toneholes are the giveaway that it is a Martin. The "L" stands for low pitch. Stencil horns are generally not worth more than a few hundred dollars, but they can be nice horns. Martin made some good stencils. That horn might not have a front F key, the use of which is integrated into modern playing styles.