Did they serve you with a notice of intent to forfeit property? If so, then you need to either retain a lawyer to help you or follow the instructions on the notice. If they didn't, you may be able to go get your property from the police department unless it is being considered evidence.
Minn. Stat. § 609.5311 governs forfeiture of property related to controlled substance violations. In order for them to overcome a challenge to the forfeiture, they need to demonstrate that because the property's owner was knew about the use or intended use described in that statute. They also have to demonstrate the alleged unlawful use or intended use occurred wih the property owner's knowledge or consent. Fundamentally, they have to show probable cause that the property represents the proceeds derived from or traceable to drug activity.
You should have received a "notice of seizure" or "notice of forfeiture" or maybe even just a receipt. If you have, then you have 60 days in which to write a "pretty please" letter asking for it back. If they don't respond or refuse to return it, then you file a claim against the authority holding it. It's essentially a small claims court matter, and the burden on law enforcement is essentially probable cause, like many criminal proceedings.
If you are not facing charges, it can also be a great way to obtain background information on the investigation, and thus know what you're facing, I.E., whether charges may be forthcoming.
Keep in mind the amount you're talking about, however, is pretty small. Most attorneys will charge you more than that just to do the paperwork. There are forms available regarding this statute. Email me, and I can send them to you. email@example.com
It sounds as if the property might be considered evidence at this point (not sure how long ago this happened). You may have to wait until their investigation is over. Of course, as the other attorneys have pointed out, if the property was part of a "forfeiture," then there is a separate process that needs to take place. Contact the police to see if they are still holding it as evidence.