Ignore the civil demand. They rarely follow up with it. If you have to appear in criminal court ask for the public defender. The judge will determine if you qualify for a free lawyer.
Note that this answer is NOT a substitute for legal advice, nor does it create an attorney client relationship. Please consult with an attorney.
First of all, you realize you have a problem. Seek out help at the University, local community, family and/or friends to "deal with the problem" -- you say you are a thief.
Second, the civil matter will work itself out (one way or another). I don't know if I would say forget about it, but I wouldn't let it stress you out at this point.
Third, it sounds like you might have been summons to Court on a criminal matter -- theft or shoplifting. Either way, they are criminal. If so (and you do not have any money to hire an attorney), then the previous poster is correct, when you appear, request that the Court appoint you a Public Defender. If you truly are "indigent," the Court will appoint a PD for you.
Now is the time (you are only 18), to put things together so you are not "in the system" for the rest of your life. You realize you have a problem -- that is half the battle. Now, the other half, "do something about it."
Best wishes --
Sit down, take a deep breath and relax. The first thing you need to do is find out if you are being charged with a felony (Theft) or misdemeanor (Conversion). Since you have no prior criminal history and the value of the items is only $70, there is a good chance the prosecutor will file it as a misdemeanor. If that is the case, simply ask the prosecutor if they have a Pre-Trial Diversion program. This is basically an agreement between you and the prosecutor. The prosecutor agrees to defer prosecution and you agree to complete certain requirements like community service or road crew; counseling; avoid an y further arrests or charges. etc. If you comply with the terms (The program is usually 12 months, although some counties have them for 6 months), then the charges are dismissed and you will avoid a conviction. These programs typically cost somewhere around $400-$600.
On the other hand, if they file it as a felony, you will need to go to court and request the appointment of a public defender to represent you.
This response is meant to provide general information only and should not be considered to be legal advice. This information is not meant and should not be construed to be the formation of an attorney client relationship.