They sold me a property from their list that was so bad that my home owner insurance company would not even cover it for "unusual hazardous conditions" They will over charge you for everything .

On another note, always shop around and  try to find contractors you can have a good relationship with that will not over charge you and that you can trust to do good work when you need them. 

most won't appreciate it, and just be like.. yeah.. this a-hole is obviously overcharging me $25/mo if that's what he is giving me.    

I've had a few "all-star" tenants over the years.My best tenant was an older black man who had been taken advantage of for many years by dirt bag landlords who would rip him off and overcharge for petty things.

Other (mostly BP'ers) have been jaded, or schooled that all TK's are overcharging. 

Can you say how much they were I don’t want to be over charged on an 8 plex im closing on soon.

I also worked with Empire Property Management, their sister company, which ripped us off on the PM aspect of the business by frequently and overcharging us on many maintenance requests (they have their in-house contractors).

Not just that but making up non existent maintenance repairs and 5x overcharging.

I rehabbed 3/8 units throughout this time and even got overcharged. 5 units remained to be rehabbed. 

However having said all of that I don't think this is an excuse to overcharge for stuff or find ways to nickel and dime tenants to squeeze extra profits out of a tenant.