I understand why you it is hard for you to spend the money on what you think is for yourself..but really it is for you to be able to give happiness and love to others. You are worth it and if they have no interest loan definitely go for it..
Who knows this new machine and the new possibilities may open new doors to friendship and learning options that you have not even thought about!!
Life is to be lived and enjoyed.... Mind you I am not saying don't pay the house payment, buy food or clothing be sensible but if the payment method is no interest and the machine is what you want .... enjoy!
Hugs
quiltinmama