A laudable Catholic custom is to have a Mass said for a specific intention. All Masses, of course, are offered to the glory of God and for the salvation of the whole world but, usually, there is also a specific intention. Anyone may request a Mass to be said for their particular intention. It is customary, when requesting a Mass, to make a small financial offering as a way of being especially associated with that Mass. However, it is not necessary to make an offering. The usual offering/donation is £10; some give less, some give more, some give nothing. Please never feel that you cannot have a Mass said for your intentions due to lack of funds.
A Mass costs nothing – except, of course, the life-saving death and resurrection of Jesus!