I attend regular book and craft fairs. Sales vary and can be anything from 1 to 20 books sold in any day at an event. Generally I sell an average of around 6 copies though. Even so regardless of sales you never know who you will meet and what contacts will be made and you also have the prmotion aspect for you and your work :-)
I'm in Lincs too. I was recently the resident author at the Stamford Literary Festival (see www.lovesey.net).
I have a table booked at Lincoln Lit Fest too so I will see you there.
Now on a related topic. Recently I have been sharing stand/table costs with a fellow author, John Nowell, who has a range of aerial photography books (See www.zodiacpublishing.org). By sharing we keep costs down.
On that subject would you be interested in sharing a table at local events? I currently have one fantasy novel and with a second due for launch in May.
I have also booked a stand at the big Knebworth Craft Fair and Country Show. This is one fot he big UK country shows and is attended by a large audience. Table fees are sky high (£200 for the two days) but I have pulled together seven of us to share the cost so it woprks about under £30 each. If you want to join us there you are most welcome and an eight attendee would bring the price down to £25 each. It is over two days 6th/7th May. Four of us are staying down that way overnight at a local Travel Inn. There is another female author staying already so if you wanted to share you could do so. Cost of the room is £26 a night (so £13 each if you shared with her). If you just wanted to send your book/s and not attend yourself then that is OK too. The cost is the same and all stock must be signed.