You should be fine with a basic tire machine that clamps onto the rim. Yes, the old center post-high-quality and cheap tire changing machines had their day, but this is the 21st century. 

Unless you plan to exclusively do steel rims, you're going to need a modern machine that clamps onto the rims. 

Not only do they make changing tires much easier, but they also are much less likely to damage aluminum wheels.

Speaking of specialty wheels, consider a high-quality and cheap tire changing machine that has a power assist, mounting helper arm. 

Even though it will increase the cost of the tire changer or wheel balancer, it will be worth it. 

Changing specialty tires can be a lucrative venture. Think of it as an investment that can pay off itself quickly. 
And it’s near impossible to change flat tires unless you have the right equipment.