Gentlefolk of GT, please help me with a seriously urgent important matter of great significance!

My usual "uniform" if I'm leaving the house (because not leaving the house always = no bra and no pants) is a tank top and a cardigan/blazer/overshirt kind of thing. With jeans, slacks, or skirts according to where I'm going and the weather. I tend to keep my clothes mostly solid colors because I HEART JOOLREEZ and think of my clothes as the backdrop for my accessories. So.

Got any advice on where I can stock up on tanks that are 1) cheap and 2) not very low-cut? For work environments, I don't like to show cleavage, so I'm looking for shirts that hit that sweet spot between gah-I'm-choking-crewneck and look-at-them-ta-tas-v-neck.

I'm counting on you all!