I have similar collecting interests - you will find the Roman period to Victoria covers a vast number of coins, so you might want to pick a few areas you're interested in (Roman London mint; Northumbrian stycas; the Plantagenets; English Civil War; George III emergency issues and tokens).
As mentioned, Numista is good for identification, especially modern coins.
For Roman coins, you want something like Wildwinds http://www.wildwinds.com/coins/ric/i.html
or Ocre http://numismatics.org/ocre/identify
If you're looking at medieval coins, you need to get your eye in. This is a good site for identification, and for demonstrating how difficult identification is https://www.rodblunt.com/short-cross-pennies
I think the main problem with selling is that you have to buy very
well to make a worthwhile profit. As an example:
You win a Constantine I follis at auction for £50. Add 20% auction fee, and £10 shipping, and that's £70. If you buy at an overseas auction, you might get hit for customs and VAT, which will add at least £12 (the customs handling fee) plus 5% VAT. So in total you've paid nearly £90.
You sell it on eBay. They want 12.8% commission + £0.30 payment fee, and if you sell it to an overseas buyer, another 2% or so. Then there's your postage cost, which second class to the UK is £2.06 (if you can keep it thinner than 0.5cm). And packaging, another £0.50 (although you can re-use the packaging you received it in if you keep it).
With all that, you might need to sell it for £120 to get your £90 back. If the buyer is not in the UK (and you use eBay's Global Selling Program), they have to pay international postage (could be as much as £20) and tax on top.
So you need to find a buyer that will pay £140 for a coin that hammered for £50 and for which you paid £90. Not easy. And that's for zero profit. You might be holding it a while.
And bear in mind, you won't sell on eBay for the same prices you pay on Roma, since Roma is a highly-respected auction house where you can trust the authenticity of the coins, while eBay is a counterfeiters paradise. For that reason, I wouldn't buy anything on eBay unless you find out the seller is trustworthy or you know what you are looking at, but buying from Roma (or DNW, Spink, CNG) comes at a premium. There are good dealers too for British coins (Silbury Coins, Chris Rudd, Halls Hammered Coins) but of course they are trying to make a profit like you, and need to live off it.
Buying a lot at auction might help (as it spreads the delivery cost over more coins) but you have to know how much each coin might sell for, or you could end up with a load of difficult-to-sell coins (which ties up your cash) and still not make the coin you wanted any cheaper. Worse, it might end up costing you more.
To do any of the above, you need experience, which takes a while. Months? Years? Specialising would help a lot, so you can spot fakes and estimate values quickly. I could probably spot a fake Roman London mint follis or a fake Saxon hammered penny, but show me anything Greek and I would have no idea whatsoever (unless it was terrible).
You might not even want to sell the coins you inherited
until you know the issue and what makes for a valuable coin. You could lose good profit in haste.
Still, if you're collecting for the fun of it, mindful that your 'investment can go down as well as up', you will have a lot of fun and soon become an expert. If you don't spend more than you can afford to lose, you can't go wrong. And you will learn a lot