There is always a price increase in March. The early prices expire. I don't think the Self Employed version was ever only $35 unless you got a discount from a partner website like a broker or bank.
You could have paid before then to lock in the lower price. Prices always increase in March. Price is determined when you print or pay or file.
You can always pay early before filing to lock in the current price.
How to pay the fees
https://ttlc.intuit.com/community/payments/help/how-can-i-pay-for-my-turbotax-online-fees/00/27388
