Did a few business trips 2013-2015, about 8-10 returns overall so I spent a lot of time improving my techniques. I'll just add my 2c.
PA does not have any sales tax on clothes/food items so generally good for the outlet malls when getting clothes. There is a wiki page somewhere with a breakdown of all the states and what they do/don't tax and the rates. Obviously PA is a bit of a hike if you are wanting to only visit the west coast.
i usually bought suitcases online, a few luggage sites have decent coupons / end of series sales so you can get some stuff cheap + free delivery (travelpro/samsonite/antler/victorinox even)Otherwise Walmart or Target stores have cheap enough American tourister or samsonite. Extra to this... If you are buying mostly clothes / soft items go to the Walmart camping section, they have a Huge duffel bag for about $15 that compacts down into its own carry bag which is great for taking over in your regular suitcase pocket.
as with the clothes, Ross/Marshall/another one I can't remember the name of are great to just poke your head into when you see them at the strip malls to see if there is anything decent, but not worth basing your whole shopping trip around.
i found Target and Walmart the best for makeup, prices comparable to Amazon and other online stores. Target have a decent range of NYX for about 50% cheaper than they offer in Oz. I was lucky once to find a heap on clearance for $2-4 each compared to about $20 in Oz. Basic brands only at these stores you will need to hit up JCPenny Kohls Macy's for other brands. Perfume is hit or miss, I normally went through Amazon as the cheapest compared to dept stores. Wife also loves bed head hair stuff, got some amazing prices on the giant bottles online, twin pack of Sha,poo was $20 cheaper than one single bottle in Aus. There is a large cosmetics chain that is in most strip malls (ULTA) but they are pretty good value also especially when they have sales on, keep and eye on their website.
keep an eye on the upcoming holidays in the U.S. And change of seasons, normally means stores have sales / coupons. I randomly found Levi's having 40% off + free delivery through their online store, was about $30 a pair USD...compared to $70-120 in Aus? Yep I'll take five. Best to know the style numbers and sizes but they are easy enough to try on at a department store and remember for later.
you can get Amazon prime membership trial for 30days, just cancel it before it ends. Free 2-day shipping on most common items that Amazon stocks, it's brilliant!
Alcohol cheapest in Walmart ( if the state allows it) or the giant liquor stores will have a massive range of stuff you can't get or have never heard of. I normally wrap the bottles up in a pair of thick wooden socks + tshirt or jumper before packing it in the middle of the suitcase. Avoid LAX duty free, seems more expensive than buying in Aust stores.
not the best time to go, but it won't improve back to the glory shopping days of $1.10 so enjoy yourself and also get a little pair of luggage scales (Amazon ~$15) they are awesome to use when packing your bags.
Walmart great for pharma or CVS as well. Even regular stuff like toothpaste/soaps/razors/toothbrushes are very cheap. Colgate optic white, giant tubes are about $5, a tube 1/4 the size sells for $7 here. Energiser lithium batteries! 8 pack $16 in Home Depo/Lowes they sell a two pack for $20 in woollies in Aus, they are pretty light also. Best buy for electronics, not amazing prices on computer hardware buy good for a look at accessories or headphones, mice etc.
regular sports stores, like find a giant warehouse style one have good deals on tshirt said and general clothing sometimes as well. Usually centred around the local sports team you can get some end of season gear for 50%+ off. Knives for camping or LED lights they will have a good range, regular victorinox in Walmart is very cheap.
enough dribble for now