Original: PV systems can vary significantly in price but prices have come down substantially since the launch of the Feed In Tariff.
Simplified: PV systems can vary significantly in price but prices have decreased a lot since the start of the Feed In Tariff.
Simplified: PV systems can vary a lot in price but prices have come down considerably since the release of the Feed In Tariff.
Simplified: PV systems can vary largely in price but prices have come down a lot since the start of the Feed In Tariff