Supporting payments through Paypal seems probable, as there is this Paypal Giving Fund that provides paying without deduction or fee.
Sadly, for some reasons my only available payment method is Paypal, so now I can't make donations :(
UPD: Thanks to all of you for answering!
Thanks for the question! There are two separate things here, which I'll address separately.
PayPal as a regular payment option
We've considered adding PayPal support, but it hasn't been a priority as we've found most donors are able to use one of our other payment methods (e.g. credit cart/bank transfer/check). Adding new payment methods adds some complexity to our payment processing operations (which we try to keep as streamlined as possible to reduce admin overhead), and given that most people use PayPal to process credit card donations, we haven't seen it as offering a significant advantage over our existing credit card payment infrastructure. However, it's useful to know that PayPal is your only option, and is some data in favour of us considering adding it. This likely won't be for a while though, but if we do get to it I'll post an update as a comment on this question.
Using the PayPal Giving Fund
Unfortunately it's not possible to automate donations made through the PayPal Giving Fund, which means it's not viable for us to offer it as a payment option at checkout. Donations to the Giving Fund have to be made through PayPal's own website, which means we can't capture each donor's allocation, and therefore all the money appears as if it's just going to the Centre for Effective Altruism (CEA –the non-profit that EA Funds is a part of). This unfortunately just isn't scalable to hundreds of donors.
For larger donations ($1000+ or equivalent), you can use the PayPal Giving Fund to make a donation to CEA, but you'll need to email us so that we can manually add your donation to EA Funds and allocate it accordingly. If this fits your situation, you can make a donation using one of the links below, then forward your receipt to funds@effectivealtruism.org along with your preferred allocation (you can see the available organizations to donate to on this page)
Looks like CEA is on there, but no ability to segment by specific funds. Probably due to it being a single charity. Each of the EA Funds (along with GWWC and other programs) are programs within CEA (a registered charity in the USA and UK).
Similarly other charities with single programs (like GiveDirectly which has Basic Income, USA etc), it looks like you can't specify what program you want it to go to.
Thanks for the detailed answer!