- 50mm F1.8 - cost £75 - i don't want to pay $100 for a lens protector
- 18-55mm standard lens - costs £70+ - i don't want to pay $100 for a lens protector
- 100mm Canon IS macro - costs £700+ - but this is ONLY used indoors
i do want to go into wedding and portrait photography...
but then... that would be another question in itself: what lenses should i buy...?
Now I see your lens list, I would say no filter.
If you plan to go FF in the future, EF and L will be my choices. EF-S line has some great lenses as well:17-55mm f2.8 IS, 10-22mm etc...
50mm f1.8 has a recessed front element and doesn't need much protection.
18-55 is quite cheap but the front element is quite solid. I've knocked it a few times and there's no scratches. If it breaks just but a new one or upgrade to something better.
The macro you said you only use indoors so I don't think you need any filters.
I have one clear filter that I use if it's really dusty or windy. All other times I use the hood for protection.