That's what I do. I have 136$, 60$ from that being all I got for birthday, 15$ for good grades, 9$ saved lunch money (so... not eating lunch for half of a month. Note, 9$ is already a lot here.) Add to that some money I saved from school trip which was cancelled (mom just let me keep the money), plus some more money I found. Found, because I don't even get pocket money. Sometimes there is money in drawers so I ask mom if I can keep it. P's will be probably the only thing I will get for my birthday.
Note that I live in a country where if you are super lucky you earn 500$ monthly in a normal job behind papers and computers... 350$ being monthly taxes. I also have 7 cats to feed which need premium food because of course they won't eat anything else, poor sister with two children who leeches money from us, genius brother living abroad (in Belgium, btw) who doesn't even have a proper job there and needs some too, grandma who can't pay bills either, and tons of other things more important than hobby.
And no, nobody from my family gives me money for occassions such as birthdays and christmas, as you can see why. Not even my mom. That 60$ I got is from my mom's friend...
I love tamagotchis, they are my most passionate hobby I have and I'm willing to spend everything I have right now on them, but really, there are things that are more important. I can't even imagine buying one tama once a month...
Plus I should mention that every time I want a tama I have to tell my mom's friend to get it off ebay. It really feels bad to ask someone to import you a toy...