In a follow up to this post, here is a sample note, in case you need a starting place. This is for someone new to the church who has recently started giving financially.
I am so glad you are here at [church name]. It has been a delight getting to know you. I pray God uses this church family to bless and support you. I want to thank you for the gifts and offerings you have given. They are a blessing to the life in ministry that we share together. Please let me know if there is anything I can do for you.