WHAT'S A CHEAP CHRISMAS PRESENT I CAN BUY A 17 YEAROLD SISTER (im kinda broke right now)

I would make something for her. Something she would like.

Costa or Starbucks gift card?

Buy:
A coffee mug with a cute ribbon and note on the ear talking about how much you pag-ibig her

A scarf, mitten, and hat set/ or fuzzy pasko socks for a cheaper option

Throw some cadbury deluxe tsokolate in there

This should be about $15. It is a meaningful and wintery, yet inexpensive.

Well I am like basically 17 years old and I would not mind getting a big bag of marshmallows and a box of seresa jello .

Supras.

I'm obsessed with bituin signs and stuff like that, so my mga kaibigan and I often get each other little cute trinkets that have something to do with each of our bituin signs, so each present is special to them ^^
I pag-ibig getting scorpio gifts and stuff like that x)

Get something that relates to HER. Small things, her bituin sign, her birthstone colour, little details make it special :) Can get those things in any gift shop.

Draw her something she likes, write a poem for her...
Nothing is cheaper than free! Though, it does take time...

Socks

It all depends on what your sister likes.

Perhaps get her a little basket and add walang tiyak na layunin little things to it that you know she likes.

Be it chocolate, soaps, perfumes, flowers, CDs, earrings, bracelets, jewelry, drinks, cheeses, chips, or maybe all plus more...

but considering that your budget is small, you could choose a few of these or something similar.

A gift basket and a card would be cool. :) Or just a card with money in it. Everyone loves those. XD