hideout is equipped with a Table Saw that can be used to create Planks from Wood Logs. The table saw must be filled with Gasoline in order to function. Filling the table saw with fuel is done the same way as filling generators. It has a capacity of 400 fuel.
It costs 25 units of gasoline to transform one log into 3 planks. During the final updates leading up to the game's final release, the fuel gauge on the table saw was changed to show markers exactly where a single log's processing would take the fuel gauge.
Given that Logs sell for 10 reputation and planks can be purchased for 6, it is technically cheaper to sell your logs and purchase planks instead of gasoline to process them.
Selling the logs and purchasing planks costs 8 reputation for 3 in total. (6 * 3) - 10 = 8. This results in a cost of 2.66 reputation per plank.
Purchasing gasoline costs 70 reputation per 200 units, 0.35 per unit. Processing a log costs 25 fuel, therefore 8.75 reputation per log processed. Plus the potential sale value of the log brings the total cost to 18.75 per 3 planks, or 6.25 reputation per plank.
Using found gasoline reduces the cost to 0.175 reputation per unit, so the cost is only 4.375 plus the sale cost of the log for a total cost of 14.375 per 3 planks, or 4.792 reputation per plank.
Therefore, it is strangely always more cost effective to purchase planks - the fuel processing cost plus the potential saleable value of the log always outweigh simply selling the raw materials that would be used for said processing and purchasing planks instead. In practice, between 1.8 (+80%) to 2.3 (+130%) times as many planks can purchased by selling logs and gasoline of equivalent processing value.