Если в прошедшем времени, то afforded

нужен ли MYSELF?

All the variants with "afford" are incorrect. Afford means to have enough money to buy something, not to allow yourself a luxury.

When you spend more money than you normally would on something for yourself, you treat yourself to something.

Тогда можно сказать "today, I can afford to buy...", что бы значило I can buy it today, right, Uly?

CAN AFFORD is tricky because it just means that you have enough money. For example, you could say something like "when I was in school, I couldn't even buy a cup of coffee. Now I can afford champagne." This is a statement about how much money you have, not your ability to spend money on one occasion – except in the negative: "I'm going to have to pass, I just can't afford it right now." If the original post is about being able to buy something, then I would say "As of today, I have enough money to buy myself an expensive book." This implies that the speaker has had his eye on the book for a while and has been saving money to buy it.