The £30 and under wax sector is crammed with some great products - my recommendations would be any of the following:-

Collinite 476s (super durable for winter)
Collinite 915 (as above and great on dark colours)
Poorboys Natty's 'Red' (what I use)
Victorias Concours (not the most durable but looks great and easy to use)
Chemical Guys 5050 (new upgraded formula)
Clearkote Moose wax (liquid / cream wax which looks stunning on red cars)
Autoglym HD Wax (not tried myself, but I know many who have on detailing world)
and if you can stretch a bit more either Dodo Juice Blue Velvet or Purple Haze, depending on whether you prefer a hard or soft paste wax

Try Tim at www.cleanyourcar.co.uk for most of the above