If your baggage is shipped separately and you’re not travelling with much luggage then the train is the cheapest and easiest way to come to Groningen. There is a direct connection from Schiphol. If you are travelling with a lot of luggage, you might want to rent a van. A taxi from Schiphol to Groningen will cost you between €170 and €250 and can be booked online beforehand.
Most bike shops in Groningen also do repairs, so have a look at one of the bike shops in your neighbourhood. Many bike shops also offer replacement bikes for the time it takes to repair your bike.
One of the most used ways to buy second-hand furniture is Marktplaats. If you do not like online shopping, there are a couple second-hand shops in Groningen. One of the biggest ones is Mamamini, where you can find a lot of second-hand furniture. City Central also offers a Vintage Furniture tour.