Sentence:  If I be not so rich, as to sowe almes by <WSD>sackfulls</WSD>, euen my Mite, is beyond the superfluity of wealth: and my pen, my tongue, and my life, shal (I hope) helpe some to better treasure, then the earth affoords them. 
Meaning of the word marked with <WSD> tags:  The amount a sack will contain.