I have overheard some players lament that they don't have the cards they need to win because they don't have money to get every card. I have collected a list of some cards that will help the monetarily-challenged enthusiast to compete against more expensive decks. All are common or uncommon cards. Consider these cards:

Scan and Full Planet Scan
These cards allow you to discover what skills and attributes you need to pass the dilemmas under a mission card. Concerned because you don't have any Engineers present? Maybe you don't need them. Look first.

Lower Decks
This card provides a bonus for your universal characters. All attributes are +2. Your universal Romulans no longer need fear Firestorm or Thought Fire. Your other universal characters can better complete those missions requiring a high level of Cunning, Strength or Integrity. But beware of Q's Vicious Animal Things and Go Back Whence Thou Camest. Both of these Dilemmas punish you for having your attributes too high.

Klim Dokachin
Playing this card limits the card draws your opponent can make. Your opponent draws no cards any turn he plays a unique character.

Devidian Foragers
This card has two good effects. Not only does it remove discarded personnel from play so your opponent can't Res-Q them, but it gives you another chance to boost the attributes of one of your personnel.

Eyes in the Dark
Don't have the skills you need in your away team or on your ship? Take a chance that your opponent does with this card and any of your personnel with Empathy (Maques works well with most decks). It is a lot of fun to use skills from one of your opponent's personnel to get past a dilemma.

Lemon-Aid
This is a great card from the Q-Continuum side deck. Are you twenty or more points behind your opponent? Free 5 points!

Mandarin Bailiff and Penalty Box
In my opinion, these two cards alone make it worthwhile to have a Q-Continuum side deck. Mandarin Bailiff gives your opponent a choice. He can either allow you to capture his personnel or he must transfer points over to you. Picard, Galen, or Mogh will either become your captive or earn you 6 points while decreasing your opponents score by the same number. That is a 12 point difference! Penalty Box takes captive one of your opponent's personnel. A penalty box found during another mission attempt will take yet another personnel captive and causes the first to be lost.

Last and possibly least are two cards that target specific characters. Their down side is that they have no effect if the target character is not present.

Where's Guinan?
Allows you to move either Guinan (where is she?) or Madam Guinan to any planet location.

Wesley Gets the Point
Well worth giving your opponent one point.

These are just a few of the common and uncommon cards that will help in your quest to win. I hope they help! Keep your eyes open for other useful cards.