So you would be normal to combination if you still get some premenstrual spots.
Any non-foaming cleanser will do, it doesn't have to be expensive. Some people love coconut oil, some people find it a major spot trigger. At least if your skin hates it you can eat it instead of through it away!
Clearasil pads are really cheap and will exfoliate preventing your spots but also making your skin look younger.
Serum really is an added extra - on a mega budget you won't get fancy anti-ageing ingredients but you can get hydration. Aldi Lacura serum is essentially the same as the much more expensive Hydraluron and good if your skin is dehydrated.
During the day, you need SPF! That really is far and away the most anti-ageing thing you can do for your skin - one with UVA and UVB protection and at least SPF 30.
You may find your SPF is moisturising enough and so not need a separate mosituriser.
Finally at night, Nivea blue pot is v cheap, lasts for ages. If you are more on the oily side you might not like it as it is quite oily.
The only other anti-ageing thing you can do is retinols - and there is no budget version for these!