@Justsorude
I think it's very rude. Your DH should have been MUCH more courteous. I would have offered the guy a tenner. I am surprised so many posters are saying they would not have offered anything at ALL.
If I took something back to someone (that I found) then I wouldn't expect anything (and wouldn't accept anything.) However, if someone came to MY house with a lost item of mine, I would absolutely offer a reward.
I have lost my purse THREE times in the past 2 years (dopey cow!) I took it into a shop without my handbag, as I only wanted 2 or 3 items and didn't need my handbag. I left it one time on the till, one time in the loo, and another time, I dropped it on the floor on the way out of the store...!!! All three times it was returned. (To customer services!)
Each time it happened, I had not much money in the purse, but I had my house key in it one time, and 2 credit cards, and also my drivers licence, debit card, and about £15 of stamps, and maybe £10 to £35.
Also membership cards for the sports centre, gym, and some other things that would be a ballache to replace. I was so grateful and happy that someone had handed it in it each time, but disappointed that I couldn't thank them, as they'd gone by the time I got to customer services.
@ReanimatedSGB
Some people are more effusive than others. Some people would do things like drive out of their way to return lost property because they are attention-seeking martyrs.
Are you OK today? I mean that genuinely. This is not the first thread tonight where you have posted something like this. How in the name of holy hell can you call someone an ATTENTION SEEKING MARTYR for being kind enough to return someone's lost property? 
You HAVE to be posting these posts for 'shock value' because no way in hell can any rational person seriously think this.