A bit of background:
I'm 33yo and size 16-18 + average height (i.e. overweight) with very messy, frizzy hair. I grew up with a very well-turned out and hypercritical mother who thought that how you looked was the be-all and end-all (controlled her weight by starving/binging) and who hated the fact that I was overweight and ugly. Shopping trips for clothes with her were a horror and I still feel happy when I go shopping on my own and don't have to step out of the dressing room to shamefully display something that's too tight 
So, anyway..... 2 kids and a FT job with long commute later, I have realised that I'd quite like to look better than I do. I work in an office and have opted for the 'black skirt/trousers and generic top' look, which is fine, except that I am surrounded by co-workers who look like they care about their appearance and make a bit of effort. I tried the other day and wore a dress (DH was working near me for the day and we met for lunch); none of my colleagues mentioned it, which made me a little sad until I realised that none of them registered my dress as being 'smart', because, tbf, it isn't. I know my self-esteem shouldn't be based on the approval of others, but it is and always has been.
Bascially, I'd like recommendations for someone like me who would like to look a bit smarter. My hair is a lost cause as no amount of product/hairdressing will make it look consistently good, but I can at least try with the rest of myself.
Recommendations for a person on a budget would be fab, thank you 