Shortest roll I've seen is 1,000' but the one I'd want is 2,500' for $125.
Seems high until you compare it to the standard 1/4" drip tubing which is almost $100 for a 500'.
The tunnel is 36' but my beds haven't made it past 25' so far. Even so, for two lines per 25' bed and 6 beds, that's 300'. Basically, the 500' roll of cheap 1/4".
The 2,500' roll for $125 would be enough to do it 8 times. If it lasts 4 years, that's 32 years worth. In reality, I could do the tunnel and have plenty for outdoor beds and still for many years.
The "cheap" 1/4" stuff has always seemed... cheap. Very variable from one drip emitter/hole to the next. Never any brand name attached to it.
500' of "cheap" - $100
2,500' of Toro - $125
Cheap is not so cheap.
The Toro drop tape is 5/8" and I've always used 1/2" mainline for the 1/4" drip tubing. I see Tees for 1/2 or 3/4 main to 5/8 drip. 1/2 supplying multiple 5/8 seems weird but the drip isn't a full 5/8 free flowing. I'm going to have to do some math for gph/gpm.
My original plan for a 12vdc system has changed to 24vdc. My pump is a 12vdc RV pump of unknown age but probably 10-20 years old. I've picked out a new Jabsco 24vdc, 3gpm pump so that's my starting point for calculations.
Quick calculation of flow rate on Toro drip tape says a full IBC tank will be equivalent to that 1" of rain per week recommendation. Four tanks will last a month. As far as rainwater collection from the tunnel, 1" of rain will be about 500 gallons or two tanks full.
All works out to nice round numbers for me.
1 tank is a good watering.
2 tanks get filled with 1" of rain.
Every 1/2" of rain I can collect is a good 1" watering.
I can store a maximum of a month's worth of watering.
Small pond at the top of the property with a properly installed supply pipe is something I've been wanting for 10 years. Did the calculations once and it would be enough pressure to run drip just off the volume of water and elevation change. No pump needed.
Meanwhile - drip and see tagline. I can get by with what I've got for a bed or two.
Last year, I abandoned the various drip small diameter systems and bought new flat irrigator hoses and controlled the total flow timing.
The various systems of which you speak are to me an enormous hassle that in the end do not function properly. As you have noted, the expense for unused tube and never having enough of specific fittings and to many of others finally got to me.
However...... more power to you and your endeavor