boots are the single most important piece of your equipment. do not skimp on the boot process. you will be rewarded with a much quicker learning curve and with the perfect choice made you will not need to buy another boot until this correct purchase wears out, which if you buy the boot in the $500 to $650 range you will buy a boot with a liner that will last up to 150 skier days.
if you have any hope of making skiing a sport that you enjoy and excel at, the minimum retail price to get in the game is $400. plus the cost of a trim to fit or custom footbed.
there is not a boot under $400 that is worth owning. under $400 you get a pos liner, shell materials that are not suitable to drive a ski, and shell geometry that is designed for the bar stool, not clicking into a binding. the ski magazines stopped testing boots under $400 years ago, because the testers could not in good conscience recommend those products to the consumer for either fit or performance. the term good ski boot under $400 is an oxymoron. and the moron part belongs to the boot suppliers that cannot understand why one, they are having trouble attracting new skiers to the sport, and two, why the ski industry is having trouble retaining skiers in the sport. and the ski retailers need to buck up and take responsibility for buying that crap from suppliers and dumping it on unsuspecting skiers...
as a beginner do you need a boot with a custom injected liner? not necessarily, but that will be better for your skiing than buying a boot that retails for under $400 bucks. Keeping in mind that i am saying that $400 is the minimum.