Basically you're going to be looking at lighting, CO2, Filtration, substrate of some sort and hardscape materials. After this you need to consider fertilisation methods and whether you want to go down the EI (Estimative Index) route, adding different dry powders daily, or an off the shelf all-in-one solution which you dose daily.
CO2 can be done quite cheap, if you go the fire extinguisher route. You can buy 2kg FE's for around £20 plus shipping. You could equally use standard aquarium CO2 cylinders which are generally very expensive, but cost about the same to refill (you may be lucky and find a second hand one for sale at a good price).
To go with your CO2 cylinder you'll need a regulator. This can be quite expensive, anything from £30 - £80 depending on brand/bargain hunting etc. Also additional things like CO2 tubing/drop checker/CO2 diffuser of some sort/bubble counter...
Lighting will also be a little pricey. If you're happy with second hand, you could get a 60cm luminaire with 2x24w tubes for around the £40 - £60 mark, depending on brand etc. New, you're looking around the £150 - £200 (for bigger brands) or maybe less from EQJ Trading (on eBay - Calling LondonDragon!)
With planted tanks the general consensus is that more flow is better. If you were just keeping fish, without wanting to do a serious planted tank you would get away with a smaller filter which turns over perhaps 3 or 4x water per hour. For planted setups we generally go for at least 10x water turnover per hour, so you're looking at larger filters. On a 60cm, something like a 1200lph filter is a good idea. Tetratec EX1200's run at about £80, as do many similar sized filters.
Hardscape is a tricky one. It depends on the sort of scape you want to create. Wood and rocks. Hardscape materials can be a bit expensive, but then you can often go walking by a river and find nice stones etc (need to be careful with wood). You can buy very nice bits of wood from some of the forum sponsors and they'll range from £5 - £40 for a piece (usually size/weight dictate the cost). Same for rocks really. Usually around £3 - £10 per kilo!
Substrates are similarly priced, if you choose to go with a complete substrate. You're looking at about £30 - £40 for a 10 kilo bag, which should be about enough for a 60cm. Oliver Knott Nature Soil, ADA Amazonia and Colombo FloraBase are the ones many are using. There are alternatives. Akadama is a soil used for Bonzai, and is about £9 for a 9 kilo bag. It has it's issues but people have great results with it.
Fertilisers vary in price also. The EI method means buying different dry salts. Each will cost around £5 for about 250g if memory serves. 250g will last 6 months, probably more. All-in-one liquids are great to start off with, as you simply tip in the required amount daily. No figuring out weights/tea spoon calculations that you have with EI. All-in-ones will cost anything from £12 for 500ml (Tropica Plant Nutrition Plus - TPN+ ) to £20 per bottle and more (ADA range). It really does vary depending on the type of setup you want to go for
Then of course, you've got plant costs. This is a massive variable. You can get them online at different places/quality. Higher quality = more cost.
Wow, hope that wasn't too rambling
All the prices I mention are guidelines really, shopping around will help. The best advice I can give is research. Research the different methods of running a planted tank. High light, low light, fast and slow growth rates etc etc. Get your head around the techniques and good practices and take it from there.
I would also say, learn to grow different sorts of plants before getting too bogged down with making a beautiful looking scape. It can be soul destroying trying to create something great when nothing actually grows.
