If you are an amateur enthusiast who uses a chainsaw mainly for cutting wood in your garden, there are plenty of devices in this low price range, ranging from handheld files to electric sharpeners which operate with either small grinding bits and or full grinding wheels.
A handheld file sharpener or basic electric bench top sharpener will come to your rescue when your chainsaw is no longer pulling down through wood the way it should. A blunt chain can make a chainsaw so much more difficult to operate and can also pose a safety risk from possible kickbacks while cutting.
If you don't fancy a cheap manual file, another option is the bolt-on type of manual sharpener which attaches to a chainsaw bar. This features a fixed guide which allows the user to accurately glide a round sharpening file back and forth across the chain's teeth. These cost around £20 and are very accurate when it comes to sharpening at the correct angle.
There are also some very affordable electric sharpeners also for under £25, including the Cooper and Stortford bench-mount device which features a guide and tooth grinder. This may not be up to professional standard, but it's ideal for the home user who wants to achieve perfect angle and depth on their chain teeth.
The Neilsen 130 watt sharpener is also worth considering - it costs around £25 and will sharpen just about any type of chainsaw chain, so it could be just the job to give a new lease of life to your dulled and worn chain.
If you are willing to spend a bit more, you might want to consider a deluxe electric chainsaw sharpener which is packed with power and is capable of precision sharpening of any chain.