Two's all you really NEED.
I play drampa-garb with two, I more than just 'get by'
As long as you can get one early game you're probably good to go. The second is to prevent prizing (mostly).
Yes it would be nice to lele every turn, but you've only got so many bench spaces. Two attackers, a support mon, mabye a draw-mon (oranguru/octillery). Add lele and your at a full bench.
Unless you run acerola, scoop up, etc, there no room for a bunch of lele.
Yes three is what the competitive players use, but if you aren't playing for money then don't invest in the third if it's going to cause you financial grief.
I'm assuming you aren't,, because those tourney guys tend to have a "F*** he price, I need it" mentality.
However, if you are in the position to get a third....do it. It's not rotating anytime soon, and it opens up more options.
I bought two the day they dropped (newer better jirachi!?!) and haven't regretted it yet. I WILL get a third, but not unless I'm playing high level. I'd frankly prefer to spend the cash on more fighting pokés, and try out (yet another) deck theme.
I might get one sooner, but that'll have to be a releaseless month or something.