Plane dating flowchart
My main users are Sweetheart era Stanleys or Keen Kutter K-series (Type 4 Bedrocks) and the vast majority were under .
They are plentiful, low cost and can be made into a magnificent tool with a little time and effort.
The new Stanleys aren't anywhere close to the quality of the older (specifically, pre-WWII) models.
New Stanleys can only politely be refered to as a kit.
These planes are well documented, it is easy to find the age and changes made thru their production history at sites like Patricks Blood & Gore and Hyperkitten has an excellent plane dating flowchart on his website if you are curious about a Stanley plane you have.
There is also a lot written about restoring them and tuning; videos you can buy too.
You can buy all the 3, 4, 5's in the flea market or ebay world often under 20$ but for sure under 30$.
No reason to buy a new one since even the 50-60's planes are better.