If you are caught possessing or using marijuana, you have committed a felony in most jurisdictions. If this is a first offense, you may be eligible for deferred sentencing or a drug rehab program depending upon the jurisdiction in which you were charged. If you by financial affidavit demonstrate to the court that you are unable to afford to pay for a lawyer, one will be appointed to represent you.
A first time offender may be eligible for some merciful resolutions that do not damage your future and label you a felon for life. It would be important to consult with a lawyer to make sure you look at all your options.