D.E.
with out question soccer is the cheapest.
you can google green country soccer club and it will list a lot of clubs. pick something close to you.
most sports can help some with the cost if needed.
it is also a GREAT thing to ask grandparents etc to help with.
The vallue of team sports and being part of the crowd.
( Or not being left out is so important)
Since you already have a few you can do pick up games at a park. kick ball is great. Just invite there friends. Bring a jug of water and a ball and GO>
ALso Scouting is a great thing to get involved in.
Cub scouting is cheap but the beniifts are WOW>
GOOD LUCK.
The families i have got to know in sports have been a real support for us. SO many BENNEFITS<<<<