"Good" is relative.
Lots of folks are okay with, say, the stock ME2 lav from the Sennheiser G3 kit. Yet 99% of professionals replace it with something else like the CountryMan B6 ($300) or B3 ($180), the Sanken COS-11 ($400 to $480), or the Tram TR50 ($240). Oscar SoundTech is up-and-coming with some nice budget lavs (around $100).
As far as wireless systems go the Sennheiser G3 ($650) is pretty much the cheapest that I personally would consider reliable. The "big budget" professionals tend to use Lectrosonics ($1,100 to $3,200 per set). Audio Technica makes some decent low-budget wireless systems ($100 to $200), but they are VHF and more prone to RF and EM interference.
I personally like the Sennheiser G3 with the CountryMan B6 as my "budget" wireless kit - that would come to about $1k per set. I would want three (3) sets.