Issue 3 of Smash! came with a cardboard Royal Navy Carrier Aircraft. In unused condition, this one rocketed itself to £304.89! (This didn't come with the original comic, just a scan of the front cover.)
Early Buster gifts are extremely hard to come by, and recently two were sold on eBay! Issue two's Zoomer Jet with original bag catapulted to £116 and issue three's Dodger Kit, also with the free bag, sold for £86! (Again, these only came with scans of the original covers.)
A Cor! Ratty Rasper without the original elastic band and metal ring, sold for just £14.50, which suddely seems really low compared to the other gifts! This was given away in October 1973.
And there are currently a few exciting items up for sale, including the Big Bang Gun from Smash issue #1, along with the original comic. It is currently up to £112.09. You can find it here.
When Wham! merged with Pow! in 1968, a free gift was given away to celebrate! It was the 'Out Of This World Flying Saucer', which is currently on eBay for £32, with a few days of bidding left to go. Click here to see the auction.