Are there any reasonably priced hotels in Oslo that offer transportation to the airport?
There is an excellent dedicated airport train in Oslo so doubt it.
Not likely. OSL options include the Flyoget express train and the local NSB train to/from Oslo S and OSL terminal, and the SAS Flybussen with multiple downtown stops.
Thank you! That helps a lot to know this.
Express train: http://flytoget.no/flytoget_eng/
SAS Flybussen: https://www.visitoslo.com/en/product/?TLp=240585