We have spent more on shoes for my 2 year old in the last year than I think my wife has, and that is a challenge!!
Whilst I am no expert when it comes to shoes, I am guessing that at an age when feet are growing so fast, getting the best fit and durability out of a shoe is very important. So, we have always had one pair of Clarks I must admit, getting them properly fitted etc. That said, however, we bought some from Asda for about £5 recently (kept losing the one pair and when in a rush needed the 'spare'

and but for the lack of flashing heel seem fine.
In the summer we got some 'surfer-type slips-ons' which are easy to pop on for about £5 and he liked them as well.
But his favourite shoes which he wears everywhere that he can get away with are his 'Thomas the tank engine' slippers. Again, just £5 from somewhere, but a good solid rubber base. Not sure if it is the subject matter on them or the quality but if he is anything to go by, the extra £25 we could have spent on clarks would be better spent on Chocolate!!! Especially as they can grow so quickly.