Don't worry too much about the price of the gifts between sisters, as long as the intention is there. Besides, you don't make money now, your sister will understand you. I think the gifts between sisters should be more thoughtful. You can fold a bottle of little stars for her by yourself, wishing her happiness forever, or folding paper cranes is also OK.
In addition, you can also go to her new house to see what she lacks. You don't have a job, so there is no need to buy too good. If it is within your ability, such as tableware, tablecloths, etc., you can buy them for her. When my brother got married, I spent a year embroidering a cross-stitch of "Happiness for a Hundred Years" for him. The couple liked it very much, and it can be hung at home as a decoration, which is very good.
In addition, you can also give her a set of travel equipment, so that she and your brother-in-law can go out for a romantic time occasionally, but such a gift is very expensive. You must look at your own financial situation before making a decision!