After missing the $25 battery strap and being reminded of it after the $100 Elite battery strap deal, I came across this one which seems like it might be a good inbetweener.
Not as big a discount as the others as seems to have been going for $109.99 previously according to C3x but positive reviews so far. If you dig through the extra reviews there is a short video review also, takeaway being that it's good but the top strap and back could have been a little better padded.
If you prefer the halo style there is also the BoboVR M2 Pro with single 5200mAh battery 10% off @ $89.10 for Prime members however if you want the extra battery and charging dock a better option would be the Plus bundle also available 10% off @ $152.10 (also Prime members exclusive price)
If you're just after a cheap halo style head strap without battery this Esimen M5 strap and protector might be what you're after @ $20.78. Minimal mixed reviews though.
Should also add these are currently in the Apparel category which is 7% cashback ($5.35)
Do you know if VRStand, the sellers, provides an Australian GST Tax Invoice with ABN? I want to get one for work but require a tax invoice and a lot of 3rd party resellers on amazon do not provide one.