Pretty simple, this particular customisation tonight. Take one pair of lace-up shoes, trainers, pumps etc (mine are £2 from Primark) and a metre of ribbon in your chosen colour (approximately 20-50p from most haberdashery shops. The ribbon I used cost me 25p per metre from my local haberdashery market stall back home.
Basically, remove the shoe/trainer/pumps laces and replace with the ribbon. Cut to preferred length (make sure you tie them up first to get the necessary amount - you don't want to go to tie your shoes only to not have enough material to tie up!). And viola, customised shoes for under £1.
I've also done this with my past two pairs of converse, green ribbon for the black pair and red ribbon for the pink pair. The best bit about this? You can mix and match colours, patterns and (to a certain extent) material you replace your laces with.