I am currently f2p I have been training str between 77 and 79 and almost 80. I am resigning at 80 in order to build additional skills, however I am likely to join the club in the near future and I would like a cape for my skills.
If I do get an ability cape, I don't want fletching or cooking though simply because it's easy I want my first 99 to be unique so I figured strength would be pretty decent. How long would it take to get 80-99 str? And which place should you train? It depends on the place you train, whether your willing to invest in pots/good food while training there, etc.
In the beginning, I'll mention - the strength skillcape is nearly as popular as the fletching or cooking ones of today. A skill such as mining, slayering runecrafting or farming will provide you with a unique cape. These skills can all be taught cheaply and relatively quickly if you put your mind to it.
Now, let's return to your question about how to build strength. Here are a few locations I'll suggest pest control. This is a terrible alternative, but it's well-known. Due to the relatively new system of pest control, it isn't that quick xp anymore. Also, it won’t get you any hit points. At times, it can be frustrating and boring. Training from level 80 to 99 would take about 8-10 weeks.
Giant Skeletons in Damisthe lair. This is my most favorite training spot. It is only accessible if you possess guthans. A salve ammy is available for training here, which provides +15% attack power and power to eliminate undead. It's a long walk to the bank so the guthans are important. However, if you're not looking to invest it, you can still train here. It's a little quicker than pest control and it's even more efficient when you are using super pots. You might get 7 to 8 weeks.
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