Weighing food is much more accurate.
It's pretty cheap too! A food scale is $17.
Got this one from Amazon almost a year ago, paid about $15 at the time. Has tare feature and multiple measurement units, works well for my needs. https://www.amazon.com/gp/product/B08BPB9T1N/
Cheap Pot to use as double boiler
For all my other supplies I get from candlescience.com (wicks, jars, oils etc). I recommend also researching in your area for local candle suppliers. I found one close to me that I can buy wax from so that saves me a ton on shipping!