Broadly speaking, you can collect this data from the car or from your home's electrical system.
TeslaFi works via an API that Tesla makes available to owners. You could always use that directly; however, learning to do so and implementing the scripts you'd need to tally the numbers up does not qualify as "easy." As
@RayCanuck says, there are alternatives to TeslaFi that may do the job. (I've never used any of them except TeslaFi and so can't comment on anything but TeslaFi.) These three options (using the API directly, TeslaFi, and apps that use the API) are the only ways I know of to get the data from the car, at least in a reliable/easy way. (I suppose you could monitor the charging screen in the car during each charge, but that would be ridiculously difficult, and you'd likely lose at least some data.)
On the delivery side, you've already mentioned a dedicated meter. That would be slightly more hassle than extracting it from TeslaFi or an app, and there's the hassle and expense of installing the meter. Another option is to use a WiFi-enabled EVSE with monitoring capabilities. JuiceNet (available on
JuiceBox and
a few other EVSEs),
ChargePoint Home, and
OpenEVSE EVSEs all offer this functionality. Personally, I own a Clipper Creek HCS-40 with JuiceNet board, so I'm familiar with what it can do. Its app provides an easy summary of individual charge sessions, but you'd need to manually sum the numbers (or write a script to pull down the data and summarize it). I don't know precisely what data ChargePoint Home or OpenEVSE provide, but I assume you can get energy-use data from them. Of course, buying one of these EVSEs would cost a lot (they start at ~$550), so they're worth considering only if you were thinking of installing a Tesla Wall Connector but haven't already done so. In that scenario, the extra cost might be worthwhile, but they will almost certainly cost more than a Tesla EVSE, especially if you want to keep a $95 Tesla J1772 adapter semi-permanently attached to the J1772 handle, rather than frequently plug and unplug the adapter that comes with the car or drive around without the adapter. There are also whole-house electrical monitoring systems that can track how much power you're consuming and even "learn" what's being used based on each device's patterns of usage. I don't know much about these products, though, beyond their existence; you can Google for more information as well as I can.
Soon after I got my Tesla, I compared what TeslaFi reported and what JuiceNet reported for my charging usage, and they tracked pretty closely -- but not identically. JuiceNet reported that I was using a little more power than the car said it received. (Note that TeslaFi breaks out both power used and power added figures, to track charging efficiency. I was comparing JuiceNet's numbers to TeslaFi's power used figures.) I suspect the difference was line losses in the EVSE's cable. The discrepancy is pretty small, but you might want to consider it -- an off-vehicle metering system will be a little more accurate than what the car reports, if you're concerned with the electricity you actually use.
Note that you can get a lot more out of TeslaFi (or other tools based on the Tesla API) than simply your home power use -- you can track charging sessions at public stations, monitor driving energy efficiency, collect statistics on software updates, etc. OTOH, there are privacy implications -- if you use TeslaFi, its server has data on precisely where your car is located at all times, for instance. A whole-home power-monitoring tool could also provide more data, but in a different way -- it could be useful for figuring out where your home electrical budget is going, and therefore enable you to target where to target electricity-saving procedures.
