Very cheap method:
1. Remove the 30t inner.
2. there is no cheap way to reduce crankarm length.
52/42/30 sounds like you have a road triple, on a road bike or hybrid, and you want to replace it with a double. There's usually more to converting from triple to double than removing the inner ring or even crankset- the BB needs replacing, the front derailleur usually needs to be replaced. The long cage rear derailleur can work in a pinch but there's a lot of excess chain and that will not be taken up otherwise. And the left side front shifter may or may not need to be changed too.
The weight 'penalty' of an inner chainring is kinda small as to what you are having to deal with in terms of all the other details.
So, what bike are you riding? A trek? a mongoose? a Walmart schwinn? A kona? What model?
For higher end bikes, converting from triple to comnpact double is totally reasonable. For entry level bikes there are diminishing returns cost wise- the Truvaitiv powerspline crank is not a high end piece of hardware at all. Unless it's your mostest favoriteist bike and you are completely satisfied witht he fit, I'd ride it for a little more as is, and look at other bikes that have a component chice you are more satisfied with.