When buying a treadmill its important to check the following from the seller:

Motor size - Known as Horsr Power (HP) Higher the faster more powerful the machine

Speed - depends on the hp of the machine

Incline - Motorised or Manual and what sort of levels you can reach

Running Belt Size - wider & longer the better if your a tall person. Its best to get a measuring tape and measure the belt size in your house to see exactly if it will be a good size for your or not

Max user weight - Its important to make sure if the treadmill can hold your weight if you are a slightly heavy person

Weight of Treadmill - Good point to check if you are to have the machine upstairs if you will be able to carry upside on day of delivery

Type of delivery they offer - some companies offer the standard delivery and some offer full set up of machine

Warranty - What type if any offered - Parts, labour etc..

You are welcome to look at our ebay shop as we are manufacturers of our own brand of treadmills.  We offer very high quality and design and very affordable prices