If you forgot to renew the lease on your apartment and 75 days later, someone else rented it, it might suck or be annoying, but you'd still have to move.
The easy fix? Set everything to auto-renew & have a backup credit card on file.
If Tenant fails to pay the rent in full before the end of the 20th day after it's due,Tenant will pay Landlord a late charge of $20, plus $10 for each additional day that the rent remains unpaid. The total late charge for any one month will not exceed $120.
Even though I definitely should have, I haven't actually enforce it beyond the initial $20 late charge. In fact, I've kind of accidentally encoded a 20-day "grace period" into my lease (a tenant could pay me on the 19th of each month with no penalty, unless I chose to move forward with lease termination). But if you haven't paid your rent by the end of the month, you could have up to $120 extra charged. I'm sure your rental agreement has something similar (probably even more restrictive).
Your registrar enforces a late fee. When it expires, your domain stops working and goes into a 27 day grace period. During that time, you can notice and renew at the regular price. After those 27 days, it goes into redemption period, which has the the late fees.
I think the most expensive domain registration I've ever paid is $9.99, and seriously if you can't afford that annually, you have no business owning domains in the first place. There are plenty of free hosting options for portfolios.