Forget the "glow in the dark" ones - they are completely useless - I have tied many types, sizes, brands over the years of camping.
Haven't found anything solar that's a good size either - at least not that fits on the guylines. Could always buy some cheap garden solar stakes and stick them by the peg.
You can buy guy-lines with lights wound through them, but they take batteries and are about £30 a guyline.
I decided to buy some Brightz Tentbrightz. Yes they take batteries but you can get a multipack cheap enough. 6 hours a night, 4 nights, and they started to dim enough to warrant new batteries although I reckon I might have got another night at a push.
Not cheap though, in the UK that is, but I got a friend in US to get them and bring them back.
A cheaper option might be Fishing Rod Tip Lights - rechargeable and only cost about £10/£12 for a pack of six.
