Trolleys

Hello, everyone

I need help with this. The text is about a young girl who plays harp. Here's a part of it:

Sefa’s second year at Trinity College of Music is going to be more expensive than her first. “Last term I lived in a hostel, which was really cheap and in fact I could pay all the rent at the beginning of the term. But now I’m going to be in a house, so my expenses are obviously going to go up, and I’ll have to find the rent each month.” She also wants to buy a car. “It’s impossible to do gigs without taking taxis, and that eats up the profits. I would like to save for a car. I need a rather large one to take the harp.”

Harps are expensive instruments. At music school in Manchester she borrowed the school’s harp, but in the sixth grade she realized that she needed her own. So her mother, Clancy, set about fund-raising. Sefa recorded and sold a demo CD which, with money from a couple of trusts and help from a family friend, made up the £10,000 she needed. But that was just the start. “Then you need insurance, trolleys and harp covers. I recently had the harp serviced – that cost a fortune!”

Her mother says, “Sefa will be studying for four years and, unless some miracle occurs, she will have to work hard to pay back a student loan debt of about £20,000, a thought that fills me with horror. Besides, my best earning years are behind me – I can’t help her.”

I know what trolley means, but it seems to me that there might be another meaning of it. I mean, why would she need a trolley?