They are providing a service. This isn't someone chillin' in their basement messin' around with a couple old apple computers. The servers are being hosted off a commercial-grade server by a hosting company (think GoDaddy).
As such, there are going to be some operating costs associated with providing this server. Writing the code for the website to act as a front page for the servers. Paying for the hosting each month. Providing tech support. Etc and so on.
I actually think that by only charging 20 cents per day and using a pre-paid model, they are actually being very generous for what they are providing. It only costs $73 per YEAR to have a server pretty much guaranteed to be online 24/7 and be bottle-necked only by each player's personal internet connection. It's only like $6 bucks a month. That's only a pitcher of beer a month (brief side note, a pitcher of beer should totally be an official unit of measure for money...think of the hilarity).
I think part of the pushback against people donating to get on a server whitelist or, in this thread's case, paying someone to host a server, is the rather young age of many people here on the forum and playing the game. Unfortunately, young folks tend to not have credit cards and paypal accounts and so view cost as an obstacle (trust me, I've been there, done that). I notice adults tend to view cost as well, a cost (I can drink 10 pitcher's of beer or pay my cable bill xD). Just general observations I've come across from the copious gaming I've done over the years.
Now some tips for you young/middle teenagers. Probably not going to qualify for a credit card at your age. What you can do is talk to your parents. Explain that you are getting older now and would like to set up your own bank account so you can learn how to use one properly before you move out. Remind them that there will be paper statements each month and you will gladly go over it with them if they have any concerns about you having a debit card. Remind them that carrying a card around is safer than a wad of cash. Convince them with your fiendishly clever logic and devilish good looks.
Grats, you have their permission, go save up some lunch money/birthday money/sell lemonade/whatever. Go to a bank and open a checking account. What you need is a debit card with a Visa/Mastercard/American Express/Discover logo on it. If it doesn't have one of those, you just have a debit card and not a debit card that can be run as credit.
Have your parents help you make a paypal payment to your server's admin or to BlockServer.Net (whichever is applicable for your situation). BAM. You just leveled up in life. Now go celebrate by planting 1000 coffee cherry trees. In compost. In space.
TL;DR: I just woke up and am rambling a bit. Good servers cost money. Pay it. It's worth it. Young folks, get help and you can pay it too.