I'm sorry this is so off topic, I would just like advice/opinions from people who will give me their honest opinion and not tell me what they think I want to hear 
I will be graduating from college soon. I had planned on just verbally inviting my parents and siblings (and their spouses) and of course my husband! But a friend told me I should send formal invites. When I ordered my cap and gown I had the option of ordering announcements, I don't want to send out announcements but they did have a message choice that included that the recipient was invited to the ceremony. I can't order less than 25 though and it's around $45! I will likely send less than five so it seems like a waste. I looked up custom ones on Etsy, and there's a lot of cute ones, but I wasn't sure if that would be tacky?
Lastly, should I invite my in-laws? I don't have a certain number of guests I can invite, I don't want them to feel obligated to come, but don't want them to feel left out either.