The biggest strength of this deck is being able to run very few creature spells while still dominating the board with creatures. This website apparently doesn't have spectral procession, but you should DEFINITELY run four. When playing this deck beware off mass bounce spells that can kill all your tokens permanently. This is not a budget decklist, rather what you should take steps towards building. The sideboard should depend on your meta, so I left it out. But being in white means that you have access to the best sideboard cards in MTG, such as leyline of sanctity, Stony silence, and rest in peace. I also love seeing four Mana tithe in a sideboard. Making cuts for spectral procession is a great way to make it lower budget. Also, adding more raise the alarm will help with that too. One strength of being mono white is the good utility lands that you can run, here are the best. Reducing the cost of the deck, this is where you should start. Just run plains instead of the expensive lands. I would recommend cutting nykthos last, since it helps you cast your expensive spells. The next place to make cuts for budget reasons is the planeswalkers. Run an extra brimaz or triplicate spirits instead of Gideon. However, Gideon is extremely synergistic with history of benalia, so cutting the elspeths is another option. Which brings me to my last piece of advice. DO NOT CUT HISTORY OF BENALIA!!! that is the single best token card out there. You NEED it to be competitive. Some varients of this deck would run black for lingering souls. Additional sideboard cards to consider: heliod, good of the sun, surpression field (if you cut the planeswalkers), entreat the angels.