From a credit risk perspective it is best to use <3% of your total credit line at any time. For you with only one card with a $3k limit this means $90. So if you consistently have a balance above that, let's say $200 you will get slightly dinged for "high utilization".

Your goal should be to always pay off the card fully each month and keep the card active. Active does not require a purchase every month but rather once a year or so, whatever prevents the card from being closed by the issuer.

You should put a Netflix subscription or something similar on the card and then use it however much or little as you want as long as you pay the balance each month.