At newnham college, cambridge.
I come from a low income background and have received significantly more financial support here than i would have at other unis. i automatically received £3500 from the cambridge bursary scheme and an additional £800 bursary from newnham on filling in a simple form, as well as money off my rent. the college also offers up to 50% refund on any academic books purchased (and will also just buy it into the library for you) and large travel grants are available as well. there are other bursaries for sports equipment, money off music lessons etc, you just have to apply.
As for 'hidden' costs - they weren't exactly hidden but in our first college bill we had to pay a £250 deposit of caution money. also if your course requires extras such as field trips, equipment, lab coats you have to pay these but again my college refunded me when i submitted a request. printing may be an issue if you're required to print lots of stuff but i have never needed to.
formals can be expensive but you aren't required to go, i only went to about 3 formals i paid for in my first year. the big cost can be if you want to go to a may ball, but there are plenty of smaller and cheaper events in may week, such as the cambridge oxfam society garden party for example.
overall i am a lot more financially comfortable at cambridge than i would have been elsewhere and college in my experience has been very generous as long as you ask and fill in the right form