What is the ruling on a woman's vow to give her grandson a gold lira on every birthday, and is it permissible for her to buy the delayed liras all at once if their price increases?

In summary: If the one making the vow (the female ponderer) intended merely a gift and not an act of worship seeking proximity to Allah, then her vow is one of permissible things. Such a vow is not considered binding by some scholars, while others say she has the choice between fulfilling it or offering expiation. However, if her intention was to attain the reward of the Hereafter, then it is a vow of an act of worship, and fulfilling it becomes obligatory. She must make up for the past years, and there is no expiation due for the delay. The obligation to fulfill the vow does not cease due to the large amount unless she is incapable; if she becomes capable, then she must perform it immediately. As for dedicating something (as a gift) on a birthday, if the intention is to celebrate, then it is a vow of disobedience, and fulfilling it is forbidden, and nothing is required according to the majority of scholars.