Joann’s has Susan Bates Quicksilver 10" singles in size 10 for $2.99 and Boye 10" aluminum needles in size 10 for $2.59 on sale on their web site.
You can get longer needles if needed, but they go up in price a little.
Use coupon code JANFSA725 for free shipping on order over $25 (which yours should qualify for).
Go through ebates.com for a 6% rebate. If you aren’t already a member of ebates, I can send you an invite so you get $5 after you make your first purchase. I get $5 also, and would be happy to donate that back to you for this cause. The $5 in your account from ebates and the 6% wouldn’t be sent to you until the next quarterly checks… not sure when those are due out.
That means 15 needles would cost you less than $27 ($1.80 a set) before tax. 30 sets of needles would cost you about $2.10 a set (since the $10 ebates money would be off the top, the more you buy the less impact that has).
PM me if you want to do the ebates thing and don’t already have an account.