You can buy soil testing kits fairly cheaply from ebay. I bought one once but haven't used it yet, cause I'm a bit of a slap dash gardener and just try stuff and see what works :)
Since you have mentioned herbs I will recommend some. Lavender, rosemary and thyme grow easily in my garden and they all are loved by bees, which is a bonus. Flat leaf parsley is easy to grow, I expected mine to last a season but it has overwintered and I've been adding it to salads and salads and all sorts already this year. I always find chives an absolute delight. In my last house they survived all year round and the bees loved them too. This year in my new house they faded back in winter but are in full force again now (without resowing). I think if I get them more established here they will probably last. Like the others I have mentioned, they take no upkeep at all.
One thing I would really recommend is growing rocket, spinach and lettuce. You might want to keep the lettuce in the shadier part of the bed, and keep them well watered, but they do exceeding well in raised beds away from the slugs. If you think how much a bag of mixed lettuce costs, it is really worth the growing space. When we have a salad in summer I take a pair of scissors and the culinder out to the garden and snip away, give the leaves a rinse and and then have a lovely salad on my plate for pennies. You don't need plugs with these, you just need some seeds and a bit of compost, and they will do really well within a few weeks.
Again going edible here but I have had a lot of success with carrotts, beetroot, parsnips, cabages, swede, radishes, shard. Fruit bushes are also good as they come back every year and you just have to be around to grab the fruit before the birds eat them all.
I've based my response around edibles since you mentioned herbs, but if there are shrubs or flowers you like, let me know and I will try to think of some easy upkeep plants for you. Otherwise, happy growing!