Costume jewellery is generally the name given to jewellery that is lower cost and doesn’t consist of precious metals or stones. It is the kind of jewellery that will be sold in fashion stores, as opposed to in jewellers. It might be made of plastic as opposed to silver or gold and will generally be for fashion purposes.
If you choose to buy fashion costume jewellery, it is going to be much cheaper than buying solid silver earrings or a gold necklace. You will find that your money goes a long way, as high street jewellery brands are often very cheap indeed and you will get more volume.
But will you get more quality? It’s unlikely – your jewellery is probably not going to be made of robust materials and could break easily. It is also more likely that the paint will chip or peel, as it will not be of as high a quality.