Ibn Abbas said: If one has intercourse in the beginning of the menses, (one should give) one dinar; in case one has intercourse towards the end of the menses, then half a dinar (should be given)
Hadith Referenceسنن ابي داود / كتاب الطهارة / 265
Hadith Gradingالألبانی:صحيح موقوف | زبیر علی زئی:ضعيف, إسناده ضعيف, يأتي (2169), أبو الحسن الجزري: مجهول،أخطأمن سماه عبدالحميد (تقريب: 8047), انوار الصحيفه، صفحه نمبر 23
It should be known that, according to our current standard, a dinar consists of slightly more than four and a quarter grams of gold. During these specific days, sexual intercourse is prohibited. If it does occur, charity should be given.