Hi Lab,
welcome to the forum.
My advice would be to find a real cheap, second hand ply-top acoustic guitar.
They sound great for
slide, and some folks like em better for slide than expensive brands.
With the added advantage of being able to easily install a p/up.
If you want a wooden reso with a spider bridge, Regal (Dobro copy)are good value for money.(Country stuff usually)
Johnson make an OK metal body biscuit bridge, for a relatively cheap price.( Blues stuff usually)
Beware of other el-cheapo reso's though, you might get stuck with a lemon.