Oxford Optik Paper 90gsm - it does wonders for me because here it is cheap, widely available at any stationery-related shop and comes in a variety of formats (spiral, bound, loose-leaf, planners, etc). The value/price in the Euro zone is unmatched IMHO.
Clairefontaine A5 bound notebooks, specifically the My Essential line — designed to answer Leuchtturm bullet journal offers. While a little bit pricey, to me it still beats Leuchtturm1917 in the value/price ratio. They’re priced similarly, but the Clairefontaine just offers a better experience with FPs than L1917.
I specifically try to use Navigator 80gsm when I print something and then intend on taking notes with my FPs. Cheap, widely available and a really good value/price ratio.