Providing fuel for a wood burner - charge or free?

[Jacky188]

Ours is a small cottage with electric heaters and a wood burner in the main room. Until now I’ve provided an amount of wood and asked guests to buy more, if needed, from the local store. 
I’ve always kept a store of wood in the garden shed with no problems. This past winter guests have taken to helping themselves in a big way. 

How do others manage the cost and use of solid fuel?

[Mike-And-Jane0]

@Jacky188 A lock on the shed would be a good start!

Depending on where/how you source your wood it may save you a fortune in electricity to supply free wood.