I called a week before my flight to arrange to take a bike. It was difficult to understand what the assistant was saying, but I thought I'd paid $75 for the bike. I also had to pay $50 for an extra bag, and $13 for the seat.
That is a total of $272.29 for a one-way flight from Portland PDX to Las Vegas. When they told me about the extra $75, I just walked away. I'll avoid Spirit in future.
The complaints page https://www.spirit.com/complaints.aspx doesn't exist any more.