Recently I let a domain expire. I found out, that in those 75 days, I had to pay $180 instead of $20 for the same domain (namecheap). So, its not the same as leasing an apartment - I think.
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.