My cat has been sick and it's costing me a fortune. Is it imperative that I bring her to the ER vet, instead of waiting until tomorrow (see details)

Sasha threw up 11 times on Saturday and I brought her to the ER vet twice Saturday night. All of her blood work came back fine and they gave her some anti nausea and liquid shots. She is acting pretty normal, minus the fact that she’s barely eating or drinking. She had a hairball this morning (or last night, I woke up to it) that was surrounded by liquid and vomited again around 10am. She was fine all day, ate some cheese but threw up again this evening. The vomit was a greenish yellow and only liquid.

The vet cost me over $400 the other day and when I called just now, they said to bring her in for Xrays because there could be an obstruction & it’s better to find out now than wait for it to get worse. If I bring her in tonight, it will be another ER visit and will cost me almost another $400 dollars. If I wait till morning, there won’t be the $100 emergency fee (I don’t know how much a regular visit costs).

She’s in great health considering her age (she’s 11) and I feel like she may have an upset stomach. I’m distraught and torn… Obviously I her health is more important than a few hundred dollars but I don’t know what to do. Any suggestions?