I found that if I feed my whites treats at 5 pm, like Don, they will be waiting up for you at that time, and remain active the rest of the night. They also fit into your budget, 20$ a piece. Wax monkey frogs are also in that range. I found blue ones on a site from a breeder for 30$. Reg tiger leg monkey are around 15 to 20$.
They most important thing for a centraly located viv is covering your animals when u first get them. Getting used to their new home can take months. I have 2 indoneasian whites, very shy at first, I covered them for two months. First I uncovered a side that faces nothing, then raised curtain slowly, with my new baby, I did a low cover, blue bubble wrap, and when I found her peeking at me above the cover, I knew she was ready for her view of the world.
The best thing is whites personality, and they'll live 15 to 20 years, they eat from your fingers and like looking at you, begging fir more food like dogs, they're quite cute. U can use sticks and wood from outside, just bake at 200 for an hour. It gives a more genuine look to a viv, when there's stuff not store bought. Check my alblum, natural wood and shelf mushrooms from the wild. Get your viv running a month before u bring babies home. And keep us posted.