Awhile back I tried monthly budget posts, and a shopping budget just wasn't my thing. Some months I ended up overbuying because it was 'within budget' and some months I felt guilty for adding something pricey that I really loved. Tracking everything precisely was also just a huge pain.
Eventually, I came up with an approach that does work for me, the 'Can Buy' and 'Can't Buy' lists. So while I have shopped a fair amount the last few months, most items have checked off items on my 'Can Buy' list or filled voids in my Spring wardrobe. That being said, H&M starting to allow in-store returns definitely prompted few online orders that may not have quite followed my lists. *cough* too many scarves *cough*.