Spirit Airlines has increased the fees for some checked bags. For $9 Fare Club travelers who pay the bag fees when making reservations before online check-in, the increase is only $1. A carry-on bag fee is $26 (from $25), first checked bag fee is $21 (from $20), second checked bag fee is $31 (from $30) and the fee to check a third through fifth bag is $76 (from $75). The fees for standard travelers who pay the bag fees before online check-in remain the same.
If you wait until online check-in to pay the bag fees, the fees for $9 Fare Club are going up $6 for all fees, started at $36 (from $30) for a carry-on bag. The fees for standard travelers have increased $5, starting at $45 (from $40) for a carry-on bag.
Bottom line: The best approach with Spirit Airlines is to not bring any bags. You can still bring a personal item that fits under the seat in front of you for free. If you do bring bags, pay for them when making reservations. Bag fees are not waived even for elite members.