Silver is the softest & easiest metal to use on jewelry that’s still safe to wear in water without making your neck green after years of use - the only way silver will turn your neck green is if you're any sort of allergic to it.
Custom silver jewelry will also be the cheapest you can get, because of this a lot of jewelers stick to only making silver jewelry since the profit margins can be so high. The difference of price between silver and gold is nearly 10 times less while still being able to look & style exactly the same (silver is also around 30% lighter than gold is).
Gold plated & gold filled are completely different things, and incorporate different metals. Unless you're allergic to silver, it won’t make your skin turn green - no matter where or how much you wear it. However, gold filled is brass. Brass does turn green and other undesirable colors when exposed to a lot of water or lotions, really almost any everyday liquid one would use. Stainless steel plated jewelry will also turn your neck green.
The safest alternative, unless you’re allergic to silver, is wearing silver gold plated jewelry used to imitate gold jewelry.
If you want to buy a piece of jewelry and stay cost effective please don’t buy gold filled! Try and stick to gold plated. The benefits of silver gold plated jewelry is to be able to wear jewelry that looks like it’s gold, and doesn’t tarnish and make your neck green. It will fade as even solid gold also fades, but you can save your money if you’re just looking for style not an investment.