buy a 100pk of strips that resolve down to .5pH ... the ones broken down into 4 colors are easy to distinguish.
this will 2-3+ years worth of spot checking for 5 USD. Probably cheaper than the meters and stock solutions to keep one callibrated... and you have to buy a new diode every few years anyway. strips are easier and cheaper in most contexts, unless you plan to use it every day (i.e. very frequently). .5 resolution is enough for gardening needs.