Hey, finally something I can answer from personal experience.

I was in a similar boat where I didn't want to sink a bunch of money into the game for a projector until I was sure the campaign was going to last a while.

You can get set up for months for about $45. If this is a problem see if your players can chip in $5-$10 each or something.

One inch grid paper is your friend. You can get 27x34 sheets of it off Amazon for about 32 cents a sheet ($31.99 for 100 sheets )

https://www.amazon.com/dp/B00AQDGJRO/ref=cm_sw_r_cp_apa_i_iIo4AbG33KRFC

For minis you can use paper as well. I recommend getting 1" binder clips and printing off your own minis. You can buy 144 of these off of Amazon for $11

https://www.amazon.com/dp/B01N2WB1RL/ref=cm_sw_r_cp_apa_i_jRo4Ab0QTWK5S

I used Publisher, but there's a free version called Libre Office Draw. Make a bunch of 3x1 squares in it on an normal sheet of paper and put in images from Google for all of your monsters. You'll want to make them double-sided so the paper sticks up (One row right side down and the other right side up).

You can fit a lot on one sheet of paper. Then print them off either at home, work/school if they allow it, or do it at a print store for less than a dollar.

Let me know if you have any questions.