Appreciate it is difficult on limited budget but....
Charity shops and ebay for better quality clothing which may last and look better than 'bargain' shops though supermarket basics often really good quality (Tesco /Sainsbury stuff)
Can you dressmake or know any one who can ? A friend who dressmakes alters her charity shop finds and has an amazing wardrobe- on benefits due to ill health but looks great and always eclectic.
Drinking lots of water for hydrated skin is free
Tweezers and good attention to 'brows ' etc -takes time.
If you are lucky enough to have family use birthday/Christmas money to buy skin care products Superdrug do a varied range and good prices.My teenager used to get some good skincare stuff in the £1-£2 range.TKMaxx also has some good stuff.
Also ask for samples- just be brave I accumulate loads doing this.The counter girls aren't as scary as they look.
My local tech college used to have it's own salon- hair colours were about £10 - waxing was under a fiver- students supervised.
Walking helps me keep weight in check - and saves me on public transport -
Paint your nails - honestly always makes me feel more groomed.
Good brows
Clean hair - don't worry about style too much a good shine is always classier I think. Clean teeth.
Try for one unusual piece a charity shop necklace or - for example a plain black T shirt and jeans with a charity shop vintage coat (leopard skin or classic trench?) Worth taking the bus to charity shops in 'better areas'
Botox fake tans heavily styled hair and high fashion clothes personally I think make women look older.
Style doesn't need money just confidence- the people I tend to notice are smiley not necessarily super stylish.
Hope that helps.