Many good points above. NEVER-EVER-NEVER EVER buy a pair of shoes (street/water/what-ever) with out trying them on before. On line? SPARE ME!
Take your waders down with you (socks too) and try them on/walk around. Two minutes will tell you if the Puppy Hunts, or not. Street shoes/wading boots don't fit? You're in deep doo-doo 'PDQ.'