Is this the way to say 'afford'? 'afford' in its meaning of 'can pay for' is not so easy to locate in Chinese. There doesn't seem to be one word. 'can't afford' is fairly easy: '买不起‘。

I have this in my text:

..., 既满足了自己买车的愿望，又能承受得起燃油费用。

承受得起 = afford ?? This 得 is its use as a particle?
Your text (承受得起) is fine. And also could use 负担得起 for can afford.

As you said, it's easy to say can't afford as ~不起, and the opposites in Chinese is ~得起, and then you could use this form for more verbs according to the context.