For Canada, finding a properly third party certified CAT III meter for $40 for $50 is difficult.
I suggest you consider the following options.
1) Fluke 101. Before Joe did his tests,
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/I suggested that the Fluke 101 would be a good option for the purposes of troubleshooting TVs.
http://www.badcaps.net/forum/showpost.php?p=504409&postcount=10BTW, despite its website name, badcaps.net does have a forum where there is a lot of information about troubleshooting TVs. Tom66, a member here as well, is your plasma expert.
2) Joe's tests suggests the Amproble AM-510 would be a consideration, but, as usual, we get hosed (pun) on the exchange rate and Amazon.com vs Amazon.ca differences.
$37.88 USD + free s/h at Amazon.com and $79.55 CDN + $31.95 s/h at Amazon.ca
3) If you can wait, this one at Canadian Tire goes on sale for about $25.
https://www.eevblog.com/forum/testgear/canadian-tire-mastercraft-dmm-new-and-old-revision-teardown/PS. Troubleshooting a plasma means working with high voltage. It could be 400VDC if PFC is present and most of your sustain boards are in the 200VDC range. Using clips for hands free operation is recommended.