Small Engines (Lawn Mowers, etc.): Is this a good buy?, overhead valve engine, first time buyer

Question
I am looking to buy a used riding mower.  I found a Weed Eater Brand about 6 years old 13HP Tecumseh Overhead Valve Engine 38" cut. It runs does not smoke and cuts.  The owner wants $400.
is this a good deal.  First time buyer.
Thanks

Answer
 Hello Prudence:

 How much Grass was the Previous Owner Cutting? Depending on the Area, the Price for that Mower Used will be from $275 to $550. Depends on the Condition of the Mower. I Suggest you Price a New Mower of the Same OEM and Figure 1/3 the Cost of a New One is what the Used one should be. I Never go Over the 1/3 Rule. Hope this Helps.

 Good Luck

 Respectfully

 John