If you are buying boots then a decent boot fitter is your best option. Everyone should have half-decent footbeds (at the very least), know how to correctly buckle their boots and use proper ski socks. Generally you should be able to wiggle your toes but your foot should not be moving around in the boot - it should feel firm and secure. If you are experiencing pain or major irritation then you may need a different boot. Some people do have very odd shaped feet and the final solution may be an injection molded boot.