There are other sources for budget gear, some of which may be cheaper than some used gear. In fact, try searching your house, first--she may already have some of the items! Here's an example. Here's another. For example, she may already have many of the clothing items (as long as they aren't cotton). If she already has comfortable athletic shoes, they'll work fine. Less than half the clothing I wear for hiking is specifically designed for backpacking. And even some of my stuff that was bought specifically for the outdoors gets worn at home year around. If you have a Costco membership, start there.

Two specific items, pack and shoes, do need to fit well--a good fit is essential for comfort! The pack should be fitted with gear inside (sandbags or other weights just aren't the same), so the pack should be bought after most of the other gear is acquired.