It all depends on the fix he wants and if he wants to call a glass glazier..idk how prices run,but also depends where the damage is,if it's back of tank or sides who cares if the plexi glass gets dull.aslong as it's not the face of the tank it's all good.

but OP like physicians and snakes said.if the glass is removable add a camel and place and seal in a piece of plexi glass,very cheap and should cost nothing much.. But look into a glazier if you like,maybe it won't be that expensive. I know me,I would go into all that,I'd just quick fix it myself especially if it isn't the front glass.