Acers are beautiful and can vary in colours. If you get a small one it can be quite cheap but larger ones can go for heafty prices! I've had an acer in my family for over 20 years. It was bought as a small one but is now the size of a small tree. I would recommend them they're easy on the eye, catch the sun beautifully and are so graceful.
There are many that have purple, or turn purple in autumn but some of the Acers and Cotinus are probably the best known but several trees have purple varieties.
Purple birch is often overlooked IMO.