[movlabc]

What if its a huge sum of money? The next person would probably take it. You can give it a charity...


???

It does not matter whether the amount is less or big. The rules of luqta (lost and found items) will apply. Here is a brief overview.

There are several rules pertaining to lost and found items in Shari’ah. At the outset, before mentioning those rules, there are two categories of found items:
1) Items known to have so little value that no one will bother to search for them nor will anyone feel offended if they are taken, e.g. to pick up a fallen fruit and eat it

2) Items of value

It will be permissible to pick up items of the first category and there will be no harm if they are taken.
It is prohibited to pick it up items of the second category and keep them for oneself. One may either pick them up with the intention of returning them to the owner or leave them as is.

If one leaves the item as is and does not pick it up, then there will be no sin upon the person. However, if he finds it at a place where there is fear that if he does not pick it up then someone else will take it and not return it to its owner, then it will be wajib upon the person to pick it up. If the person feels certain that he will not be able to fulfill the responsibility pertaining to such items, then it will be forbidden for him to take it. Even if one suspects that they will not be able to fulfill the responsibility, then it is better to leave it.
If one feels certain that they are able to fulfill the responsibility after picking up the item, then it is better to pick it up and do so and one will be rewarded InshaAllah. If the item is picked up then the following steps should be taken:

a) Firstly, one should get witnesses to prove that the item is being taken with the intention of returning it to its owner.

b) One should go to common public gathering places and advertise in a newspaper and make a ta’rif (general announcement) and clearly announce that the particular item has been found and that the owner should come and claim it.

c) One should not announce what exactly he has found. The item should be described generally. If one claims to be the owner of the item, he should give a clear description of the item.

d) After a sufficient amount of time has passed without the owner coming to claim the item, and there is no more hope in finding the owner, then the person can either hold on to the item with the intention of returning it to the owner, or he may give away the item itself or an amount equal to its value in charity.

e) Finally, if the owner comes forward after the item has been given away in charity, the owner can either approve of the item being given away or he may demand the amount equal to its value from the person who gave it away in charity.

يجب أن يعلم بأن التقاط اللقطة على نوعين: نوع من ذلك يفترض وهو ما إذا خاف ضياعها، ونوع من ذلك لا يفترض وهو ما إذا لم يخف ضياعها ذلك ينافي أخذها، أجمع عليه العلماء، فاختلفوا فيما بينهم أن الترك أفضل أو الرفع، ظاهر مذهب أصحابنا أن الرفع أفضل؛ لأنه لو لم يرفع هو ربما تصل إليها يد خائنة، وبعض المتقدمين قالوا: الترك أفضل؛ لأن صاحبها يطلبها في المكان الذي سقطت منه، فإذا تركها وصل إليها يد المالك، ومن العلماء من قال: إن كان ..... .... يأمن على نفسه الخيانة، فالرفع أفضل، وإن كان فاسقاً لا يأمن على نفسه الخيانة فالترك أفضل، ثم ما يجده الرجل ......... .... أن صاحبه لا يطلبه كالنورة في مواضع مختلفة، وكقشور الرمان في مواضع متفرقة، وفي هذا الوجه له أن يأخذها وينتفع بها ................ وجدها في يده بعدما جمعها، فله أن يأخذها، ولا يصير ملكاً للآخذ، هكذا ذكر شيخ الإسلام خواهر زاده، وشمس الأئمة السرخسي في شرح كتاب اللقطة وهكذا ذكر القدوري في «شرحه» في المسائل المنثورة من «كتاب الحظر» والإباحة.
(Al-Muhitul Burhani, 8/166, Idaratul Quran)
(Raddul Muhtar, 4/476, HM Saeed)
(Al-Hidaya, 2/613. Maktaba Shirkah)
(Bahishti Zewar, 1/353, Zam Zam) http://www.askimam.org/public/question_detail/17657