I have withdrawn my paper after it was accepted for financial reasons.
Can I resubmit it to the same journal ?
That depends entirely on the journal itself. If the submission process is automated, you could just try and see what happens. But you could, and probably should, contact the editor for information, explaining the earlier withdrawal and why that isn't an issue at present.
But, I assume some journals wouldn't like to reconsider it. And take care that it isn't a predatory journal. They might want to accept it again, but you may have better options elsewhere.
Journals and editors want to accept and publish your manuscripts. If it has already been reviewed and accepted, that is even more reason for them to publish it. They need citations and a better reputation as much as you do.
If you are unable to pay fees (such as open access fees) at the moment, you should contact the editor if you still wish to publish with them in the future. You do not want to wait for reviews again if it can be helped. Even if the new reviewers approve of the manuscript as well, this is a time consuming process for everyone. It is better to come to some arrangement with the editor or at least notify them in case an automated system rejects your resubmission.
The exact process will vary between journals. Only an editor will know the policy for a specific journal. They will want to help you. Don’t hesitate to contact them about questions of this nature: it is their job to handle these matters.
Make sure you know what you're doing before resubmitting.
If you submitted to an open access journal, then it's nonsense to resubmit because it will just lead to them charging you the submission fee again. If you submitted to a hybrid journal, then you shouldn't have withdrawn it in the first place because you can simply decline open access. If you needed a discount or a waiver, you could've negotiated for it without withdrawing.
In a nutshell, if you withdrew the paper because of financial reasons, and this was the right decision on your part, I can't see why you would want to resubmit to the same journal unless you've found funding to pay for open access. If this is indeed the case, then just write to the editor saying so, and do whatever she says.