dude, u dont need to buy any special lights for your shrooms to grow. they do just fine even in mediocre indirect light (even if its not sunlight).
people who buy lights for shroom grows do it for stealth growing (in closets for ex.)
if your substrate isn't pinning in the balcony, then its not the light thats the issue, but some other factor. maybe the sub dried out and is almost out of water due to the sun. dunking the sub would help in this case. or maybe the humidity is low and not enough fresh air exchange?
you should take some pictures and post about the details so that a better analysis can be made.
but you certainly don't need to spend money on buying lights, because shrooms use light for determining which direction to grow in and not for photosynthesis like plants do.
yesterday, i found to my surprise that my sub was colonized and started pinning while it was still wrapped up in a black bag with tiny holes with VERY little incoming light.