Buying trainers is a simple process
Do they look nice ? Try them on
Do they feel comfy ? Check price
Is the price okay ? Buy them, if not revert back to "do they look nice" with a new pair, rinse & repeat
If you need help buying trainers then I don't know what to say
Are you able to go try on every pair of trainers that you might like? I have about 5 or 6 pairs that I wear regularly, dont have a great deal of money, or style but I like them. All but one arent available locally so had to get some ideas from others and then take it from there, hardly rocket science is it!