front picture

If it was not in danger of rusting through and was running / driving well- they are a nice little mower. Sat for 2 years, likely means carburetor issues and who knows if you can't try it out first.

this is a light duty mower that Is sold in department stores and home improvement stores. This is manufactured by MTD - the same company that builds Troybilt, Bolen, White and mowers for selected department stores such as Craftsman. Owners usually keep these for 7 - 10 years before buying another mower.

The engine is a Chinese design that seems to run ok. Ethanol fuel may have affected the carburetor due to it's corrosive effects. Most dealers probably do not have many parts, however, the parts are normally available from the MTD distributors. May sure the engine runs properly before buying. Also check all the cables for signs of corrosion and smooth operation. Check the height adjusters for smooth operation. Make sure the wheels do not wobble. The rear drive is a plus over front drive.

Mowers like this usually sell for $250 = $300 new. I often see these for $75 - $85 (used) that do not need immediate work.

Judging by the picture, I see normal surface rust on the deck which will be removed by normal use. The blade being an expendable item, its condition is not critical, but it looks okay. I would take it off, sharpen and balance it. Overall I see a lightly-used mower that has simply been neglected.
You made an error when you tilted it up with the carburetor down - most likely gas and oil got into the intake tract/cylinder, so it may be locked up by fluid when you try to pull the starter. Typically you would change the oil, replace the pleated paper air filter, remove the spark plug and pull it through to blow out some of the oil. Then it will smoke for several minutes after starting.
I would not pay $150 for it because so much work is needed (probably) just to get it running, and then you may encounter other problems. If I could look it over and mess around with it a little, I might give $65 for it.

Actually IMO the under side of the deck not that bad. Naturally it's going to show surface rust. Most owners don't even clean the underside of the deck. let along know the condition of the blade which IMO not bad just surface rust.

I agree with others now way I would give over $100 for it unless I was desperate and it ran fine. I would expect to pay least half the original cost in pristine condition, price goes down from there. I see this as above average condition provides it runs correctly and the oil was changed at least once in blue moon $100 bucks max.