Replying to How essential are new boots?

How important is it to buy new 2-300 dollar pair of boots opposed to purchasing a used pair at the shop to save a little money so I'll be able to afford more than ramen for the next few weeks? Obviously it's better to buy new... That's not what I'm asking. Also what should I look for when buying used boots if it comes down to it? & when is it best to have stiff boots vs medium flex vs full flex? More than likely I'll just look for boots online cause my local ski shop usually only has a couple brands to choose from. Thanks in advance

Edit: if you have any boot recommendations that won't break the bank, link me