There are cheaper ways to do it.
Instead of build-a-balls, ask on Freecycle or friends/family with kids for old ball pool balls and make the holes yourself.
Most of the blue tubing used on allotments is old water pipe. Again, ask on Freecycle or scavenge from skips/building sites for leftover offcuts. I have some old curtain track as well for shorter crops.
I use all the methods you mention. I have shallow chickenwire tunnels for newly sown seeds/seedlings. I have a chicken wire cage I drop over larger seedlings and use blue hoops and nets for the largest things. All my chicken wire and blue pipe has come from Freecycle. I buy nets from Wilkos/eBay.
The hoops work best if you push them over or inside pipes sunk in the ground. They also need bracing with canes to keep them rigid.
I tend to use timber/steel poles to weigh down the edges of nets. It's easier to pick up and replace than individual pegs and more effective at stopping birds getting trapped inside.