You could just opt to dose fertilisers using the EI method - that way you won't have to worry about nutrient deficiencies and thus saving a lot of money on buying test kits.
I have NO test kits whatsoever and I've been running planted tanks for about 5 years now. I use injected CO2, 6 hour lighting and EI dosing of fertilisers and I cannot complain.
Plants use Nitrogen, Phosphate and Potassium as the major components. And then Trace elements (such as iron, copper, magnesium...). As long as you have all these dosed correctly then I wouldn't worry about test kits.
I hope this helps,
Planted Tank Enthusiast
80L Opti White heavily planted open-top tank: JBL CristalProfi 1501e containing a range of filter media; EI dosing; pressurised CO2 with Lily Pipes and Surface Skimmer; Finnex Planted+ LED Light. Neons, Embers, Pygmy Corys, Amano's and Oto's ..and I'm in love with it.
If I have helped you or require further information / advice, then please do not hesitate to drop me a message!